Afterwards Laila Harre and Hone Harawira said the Prime Minister broke the rules more than once and should have been kicked out.
"He broke the rules time and times again. He never got told off," Mr Harawira said."We're in his electorate. So that's life.
"Unless you're deaf, dumb and blind, there clearly was favouritism, but I'm not crying about it.
"Ms Harre said a different set of rules applied to Mr Key."I thought it was one strike and you were out. He had three strikes and he was still in.
"Everybody else behaved themselves, as we said we would. We got a really strong message out. "She said she chose not to talk about local issues as she has never courted the electorate seat.
"I could have certainly answered the question about the roundabout, but I chose to highlight the fact that we are after the Internet-Mana party vote."I think the audience would have liked to participate a whole lot more. They were more ripped off than the politicos."
Mr Harawira said if someone had yelled out a racist comment while he was speaking, he did not hear it."If they did, I get that all the time. That's life."
The candidates are now speaking to media outside the venue. This ends the live updates from the Helensville candidates debate.
9.20pm: A pause while the convener fiddled with questions lead to the end of the meeting.
Someone in the crowd called out, "Cup of tea time", and then when asked if they wanted to finish, the crowd said a resounding "Yes".
9.12pm: John Key was again pulled up for breaking the rules, talking about Labour's policy on NZ Superannuation.
Holly Ryan said he "came very close" to a warning, adding: "Do you wanna go now?"
8.55pm: Labour's Kelvin Davis said "all the evidence shows" that lifting the minimum wage would boost the economy by putting more money into people's pockets, and would not cost jobs.
John Key sitting next to Mr Davis sat shaking his head and muttering.
Key used his next answer to a question about state care to talk about a $16-an-hour minimum wage that could possibly cost up to 6000 jobs.
Pita Sharples took a question on Whanau Ora, saying it built family structure rather than treating one person and "hoping for the best"
Asked about a local roundabout, Laila Harre said: "I think I'll leave that to your local MP who won't have the responsibilities of high office after September 20."
8.44pm: Internet Party leader Laila Harre said the party would withdraw from the five-eyes agreement and have a Royal Commission of Inquiry into New Zealand intelligence agencies.
"We will repeal the GCSB law changes that occurred last year."
When asked what she would do for the Helensville electorate, Laila Harre said: "Change the Government."
8.42pm: John Key was pulled up for talking about child poverty when he was asked a question on health and safety.
When he said the health and safety issues was a local government issue, Holly Ryan said ultimate responsibility lay with central Government.
This drew some noises form the crowd, and she withdrew, saying she would stay out of it.
8.30pm: Hone Harawira was asked about the wage gap between New Zealand Maori and Australian aborigines. He said wages are so bad, they were almost as bad as aborigine.
"People are out of work for too long, they have become almost unemployment."
He talked about community work programmes as lifting people out of unemployment, but Kelvin Davis talked about education as the key.
Harawira said feeding kids in schools should start tomorrow.
"Making houses warmer, more state houses, more jobs so people can put money back into their families ... they are all really important, but they take a while to happen."
8.23pm:The first randomly drawn question was directed at the Labour Party, asking why 17-year-olds in state care are pushed out into the adult world before they can even sign a tenancy agreement.
Corie Haddock said Labour would put the age up to 18, and "on a broader level review state care as a whole".
John Key said there were no plans to remove the Christian prayer in parliament, nor would he ban religion in state schools. He said schools could decide not to use religion in schools if they wished.
"That's part of the choice we offer in our schools."
Answering a question on young criminals, John Key said recorded crime was dropping, and police technology had been upgraded.
The Government also looked at who were causing crimes, and responding with drug and alcohol rehabilitation services, among other measures.
8.18pm: The Greens are not standing in Te Tai Tokerau, but Tamaki Makaurau candidate Marama Davidson took the stage to applause.
"What will our words be to our descendants in seven generations to come? Will they have embraced how to share better ... how to care better? Will they be reaping the benefits of a smarter economy that we can plant the seeds for today?"
Furthermore, Marama Davidson said a nurse in schools would help Maori in the north, as well as free lunches, and social services in schools so that they connect with families.
8.14pm: New Zealand First does not have a Helensville candidate, but MP Andrew Williams took the stage repeating the party slogan: "It's common sense."
He said New Zealand First had a good record for looking after pensioners, and an extra 1000 police under the Labour-led Government.
Stopping foreign ownership was the party's main message, as well as buying back the Government's share of power companies - a message that drew applause.
But the applause died out to a single person when Mr Williams talked about the party's KiwiSaver policy for every newborn baby, and disappeared completely when he moved on to GST-free household food items.
Andrew Williams said the party was for one law for all, regardless of their ethnicity.
"We all want good health, good education, good jobs ... it shouldn't be based on any ethnicity."
8.08pm: Independent Penny Bright was introduced as "uninvited" and "threatening injunctions", and invited a few giggles in the crowd when she proclaimed she wold win the electorate vote.
She said she was a defender of human rights and opposed to the TPP and "this neo-liberal, pro-corporate model".
Ms Bright said "contracting out was twice as expensive as in-house provision".
Cutting contracts would allow the Government to put billions of dollars towards social services, the self-described "fiercely independent candidate" said.
8.04pm: Act's Phelan Pirrie said parties offered bribes for votes.
He said Act would be in parliament because of Epsom, so all party votes will count.
He talked about three strikes and extending it to burglaries, claiming it would reduce burglaries by 100,000 in three years.
He said a low flat tax would boost economic growth. Over time the top rate should be no more than 20 per cent.
Mr Pirrie said green tape (related to the Resource Management Act) was restrictive to business.
"Every party vote for Act is valuable."
8.02pm: Mana Party leader Hone Harawira highlighted child poverty.
"Our children are far far more important ... We could have done without the tunnel to the bloody airport. We could have done away with the holiday highway. There's so many things that are just no longer important."
People in his community have been "poor for so long" that they often make the wrong choices.
"And what do we do? We hammer them for it."
He asked people to go home and make decide child poverty is most important issue.
7.58pm: Ms Harre closed by canvassing Internet-Mana policies, from a ban on deep-sea oil-drilling, to scrapping National Standards, and bringing in free tertiary education.
"It is time to restore integrity to our political system."
She took a shot at the Government's SkyCity convention centre deal and The Hobbit laws that she said were changed for Warner Bros.
"We will hold our intelligence services accountable for the illegal spying on at least 88 New Zealanders.
"Our independence is not up for sale ... We can stop the TPP from undermining our independence."
She was cheered and booed as she crept over five minutes.
7.51pm: Internet Party leader Laila Harre said thousands of people had filled halls filled by ordinary New Zealanders across the country for the Internet Mana roadshow.
"That message is clear. Change is possible."
She took a shot at John Key, recalling the protests in 1981 to the Springbok tour.
"I remember which side I was on."
The rock-star economy left a trail of destruction in its wake.
The country was in crisis, she said.
"At the top of our list is a plan to unleash the creative potential of New Zealand in the digital age.
"Raw commodity prices have been at record levels, and yet we have only managed to get unemployment down to 5.6 per cent. That is a disgrace."
Maori Party candidate Te Hira Paenga said the party made no apologies for partnering up with National in Government.
"The Maori Party has had a good rate over the last six years. It's not only good for Maori, but for all of New Zealand."
Mr Paenga asked for a show of hands of those on Te Tai Tokerau roll - the tiny show of hands elicited some warm laughs.
"I'm not here just to look good, flash, or even be sharp ... a vote for me is a vote of faith."
The crowd gave him a huge cheer.
7.43pm: Labour's Helensville candidate Corie Haddock talked about how his party's policies connect to people through homes, families and jobs.
When he and his wife bought his first house, he said it was "the worst house in the best area".
They struggled to pay, but were grateful they bought when they did.
"The reality is, we wouldn't be able to buy now.
"Others have had to move out of Auckland in order to get on the property ladder."
Auckland has become a speculators' paradise while those on low incomes are priced out of the market.
He highlighted Labour's housing policy to build 100,000 houses over 10 years.
"We're going to cut down on speculators ... and introduce a healthy homes guarantee to make sure every rental is healthy and dry," Mr Haddock said.
7:38pm: Labour's Te Tai Tokerau candidate Kelvin Davis said Labour would make New Zealand a better, fairer society.
He started by saying the policies had all been paid for, and then repeated that for emphasis - the Government has tried to pick holes in Labour's budget.
He outlined Labour's housing, health, including free GP visits for over 65s, and education policies.
He had a poke at National's education plan for teachers of excellence to roam across many classes.
"We don't agree that it's correct to take away an excellent teach from a classroom for two days a week. Quite frankly that doesn't work."
7:33pm: Deborah Dougherty, from the Conservative Party, mentioned victims, marriage and parenting.
She pushed party policies including binding referenda, the first $20,000 of income to be tax free, and tougher sentences for criminals, especially violent criminals.
"These are sensible changes that the vast majority of decent New Zealanders want."
She said the drinking age should be 20.
She railed against the anti-smacking law.
Two "good" families a week were investigated under the law, she said.
"You can actually make a difference. Your vote Conservative can bring change.
"Vote for the restoration of reason."
7.30pm: John Key was up next - the order was determined by rolling dice - and he rose to huge cheers and boos from the audience.
Immediately the cheering front row was warned.
"None of that behaviour, please," the convener told them.
Mr Key said the last six years included the Christchurch earthquake and the Global Financial Crisis, and said in those circumstances, "New Zealand is doing very well".
He talked about New Zealanders staying in the country instead of heading to Australia, lower recorded crime and a "strong" environment record.
He highlighted ultra-fast broadband and roading as part of the development programme by the Government.
He said an important local roundabout would be built in the next three years, prompting applause from one crowd supporter, which prompted a glare from convener Holly Ryan.
Key mentioned Kaipara College as a local issue, saying it was rebuilt after a fire.
After applause, convener Ms Ryan dished out two more warnings for crowd cheering.
7.20pm: Green candidate Kennedy Graham started by talking about sustainability, finite resources, and Green philosophy.
"If there is one thought that underpins Green belief, it is that we have one planet to share."
The Greens were about freedom and equality, and considers humanity not only today, but future generations.
"We love New Zealand and we care for the planet ... the Green story is about values, and it looks beyond today."
He called the 100 per cent Pure brand as a deception, and called for a cleaner environment, better use of public transport and moving to a carbon-neutral economy.
"It will not destroy the economy. It will save it."
He had a veiled dig at the Government, saying New Zealand's economy was dependent on the price of milk and the selling of land to produce it.
Convener Holly Ryan said the rules were five minute speeches for each candidate.
If they referred to another candidate or party, they would get a warning, and if they did it again, they would be removed.
The same rules applied to the crowd.
The rules were hers alone, and had nothing to do with John Key, she said.
Laila Harre was last to arrive, and there were some awkward sounds from the crowd as she shook hands with John Key.
6:58pm: John Key has arrived at the Helensville debate, to cheers and boos from the crowd.
Cheers and boos as JK arrives. pic.twitter.com/i3dzEmslsv
: A packed crowd of at least 300 turned up at the Kumeu Baptist Church this evening for the keenly anticipated candidates' meeting for Helensville and Te Tai Tokerau, featuring several prominent political players including John Key, Laila Harre, Hone Harawira, Colin Craig, Kennedy Graham, Pita Sharples, and Kelvin Davis.
Many people overflowed out the doors and had to watch the meeting on a big screen.
There were National Party placards and Save Maui's Dolphins banners on display in the audience, as many parties shipped out support crews.
Mr Key had previously downplayed the debate, saying that people may be disappointed if they were expecting fireworks.
Candidates that mention each other by name or talk about other parties risked being kicked out, with the event meant to be about policy debate.
Listed candidates included John Key (National), Corie Haddock (Labour), Kennedy Graham (Green), Laila Harre (Internet), Deborah Dougherty (Conservative), Phelan Pirrie (Act) and Penny Bright (independent) for Helensville, and Kelvin Davis (Labour), Te Hira Paenga (Maori), Hone Harawira (Mana) for Te Tai Tokerau.
Mr Key won Helensville in 2011 with a 21,066 majority. Mr Harawira won Te Tai Tokerau with a 1165 majority.
Maui's dolphins sighted at Kumeu Baptist Church. pic.twitter.com/YtvPiFbClx
Plenty of Team Key here in Kumeu too pic.twitter.com/R4qN2THVVU