Here is audio of Lizzie Marvelly's performance of 'Amazing Grace' -
In Dunedin, a co-organiser of tonight's event, Izzy Lomax-Sawyers, said the death had shocked and saddened people.
"I think a lot of people have felt a lot of shock and shame about this happening in New Zealand."
Dunedin Mayor Dave Cull and Dunedin City Councillor Aaron Hawkins were among the speakers to address the crowd.
Cull said he felt a sense of shame over what had happened to Millane.
7:55pm: The Auckland vigil is concluding and everyone is being urged to get home safely.
The vigil in Wellington has finished with the crowd standing to sing
People are now laying candles and flowers on Grace's vigil.
Lizzie Marvelly is taking centre stage and will sing a tribute to Millane.
Marvelly has chosen to sing Amazing Grace and members of the crowd are starting to join in.
Candles are being held up in the air towards the sky as she continues to sing.
7:40pm:Back in Auckland, A spokesperson for the Lucie Blackman Trust said he's seen hundreds of cases like Grace but nothing like the outpouring Kiwis have shown.
There is complete silence among the crowd as White Ribbon ambassador Mark Longley addresses them.
He said we're starting a new year shortly and we need to change our culture towards women.
He reiterated to those who said they're not apart of the problem, "you need to be a part of the solution".
Rain drops are starting to fall as Longley talks about seeing his daughter and trying to wake her up after she was murdered.
Many of those in the crowd are also wiping away tears from their faces as the light rain continues.
7:33pm: In Wellington, Greens co-leader Marama Davidson said gender violence had been a long standing issue in Aotearoa.
She said since the strangulation charge was added to law on December 3 there had been 36 of the charges laid by police.
"That's an indication of the work we have to do to clean up our own act"
7:25pm: Director for family harm in Auckland, Vaughan Graham, said Grace's case is not a family harm case.
"I'm here to speak out against violence towards women," he said.
Every four minutes police attend a family harm incident.
Graham said speaking out can help police, urging those who know people are abusing their families to speak up.
"Please stand up to violence against women, Kia Kaha."
A spokeswoman for Shine, a national domestic abuse charity, said: "Women have been learning to protect themselves and it isn't working."
The stage is at the bottom of Federal St, closest to Victoria St.
Around 1000 people are there now - men and women all coming together to unite.
7:22pm: Dozens of people, including men, women and children of all ages, gathered at Clive Square in Napier tonight before walking to up Emerson St to the Napier Sound Shell to pay their respects to the Millane family and press for a change.
Rob Burden from Havelock North said 11 people had been killed in the past few days and it was time to take a stand against violence.
"I travelled over to Australia when I was 18 and I felt safe, people should be able to feel safe wherever they go.
"I also think the parents of Grace should be able to see a lot of us get to gather to let them know we do care."
Fellow participant Jill Currie, who attended the vigil with her 15-year-old daughter Caitlin, agreed.
"It's not just violence against overseas tourists, it's also violence against children and the rise in violence at this time of year anyway. It's a chance to promote non-violence."
7:20pm: In Dunedin, scores of people have turned out in the Octagon.
7:15pm: In Wellington, the vigil has begun in Wellington and the square is packed.
There are tears from many as they hold their candles up for Grace. Green Party co-leader Marama Davidson and Wellington mayor Justin Lester are about to speak.
7:05pm: More than 500 have packed into Federal St underneath the Sky Tower in Auckland for a second vigil.
Candles are being dispersed throughout the crowd as they patiently wait for the event to start.
Detective Inspector Scott Beard said he wanted to thank the investigation team and said their goal was to always find Grace.
6:55pm: Hundreds of people are beginning to gather in Te Ngakau Civic Square in Wellington for a candlelight vigil.
Grace's photo is lying on the steps surrounded by candles and flowers.
There's only quiet chatter and a sense of grief and sadness in the square.
The Michael Fowler Centre next door while light up white for Grace when the sun sets.
There are plenty of young women in the crowd, far outweighing the number of young men.
6:31pm: Mikaelea Varcoe is now performing Skinny Love as a musical tribute for Millane.
6:30pm: White Ribbon ambassador Mark Longley is stepping up to speak.
Longley, father of murder victim Emily Longley, said the turnout tonight is fantastic.
"I sat all day trying to think of what to say but I couldn't find the words," he said.
"Grace's story really resonates with me ... I felt for her father who made the long journey over her hoping it was all a misunderstanding and Grace had been found.
Longley said around 105 women had been killed by their partner in the eight years between his daughters death and Millane's.
"The next victim is out there ... and we're going to get 14 women murdered next year.
"I've heard a lot of men say they're not the problem, but you can be part of the solution."
6:20pm: The crowd is being asked to stand for a two minutes silence.
6:14pm: Auckland Mayor Phil Goff thanks everyone for turning out tonight so they could honour her memory.
"We need to change our culture. We need to change the way too many men act towards their partners and their children," he said.
"Tonight our hearts go out to the Millane family. She should have been safe here but she wasn't."
Goff said the domestic abuse levels in the country reported to the police and other authorities is disgraceful.
6:10pm: "To the Millane family we are so so sorry ... as a country we didn't do our job to keep your daughter safe," said White Ribbon's Anna Campbell.
"Today while we remember Grace we also want to remember the 14 women every year that lose their life to violence in New Zealand.
"While we remember Grace, we remember those women too."
New Zealand should be a country where woman can wear what they want and do what they want, Campbell said.
Campbell, holding back the tears, said White Ribbon have never held a vigil, and she hopes they will "never have to again".
6:06pm: Auckland Mayor Phil Goff and Detective Inspector Scott Beard are among the crowd.
Hundreds of mourners are at Saint Patrick's Square in central Auckland to pay their respects to Grace Millane.
A silence over the square relays the somber mood New Zealanders all over the country feel.
A shrine sits at the foot off the cathedral with banners for White Ribbon reading, "You can stop violence towards women".
Patrons are queuing to light candles on a white table near the Cathedral doors.
A wreath of flowers sits on the table with a candle in the middle. The ready of the table features an array of candles too.
Sitting in front of the table is a wicker basket with White Ribbon pins in them people are encouraged to take.
Meg Andrews said it was sad it took this kind of event to happen for New Zealand to band together.
She said Millane's death was a horrible tragedy and she was heartbroken it happened in her city.
"I work in the city and grew up in the Waitakere ranges so it feels really close to home," she said.
"I came here today to pay tribute to the family and show New Zealand is against domestic violence."
New Zealand public to host vigils throughout the country
New Zealanders will turn out to vigils hosted throughout the country tonight to remember and express grief towards the alleged murder of Grace Millane.
The British backpacker went missing earlier this month, sparking a major police operation which concluded with her body being found in the Waitakere Ranges on Sunday.
Groups and organisations throughout New Zealand have planned vigils in the memory of Millane, who's death has rocked much of country.
Millane was visiting New Zealand as part of a year-long overseas experience before she went missing.
Following an Auckland Police investigation, a 26-year-old man was arrested and charged with her murder.
The man fronted the Auckland District Court on Monday and was given interim name suppression.
In Auckland, the White Ribbon group are hosting a vigil at St Patrick's Square at 6pm. Also in Auckland, another vigil will start at 7pm nearby on Federal St.
White Ribbon said it was a chance for New Zealanders to stand together and make a moment to say "time's up on violence".
Elsewhere, in the country's capital of Wellington, another vigil is being held in Civic Square at 7.30pm.
"Many of our gut reactions are to want to say this isn't New Zealand, this isn't us," the Wellington vigil organisers wrote.
"And to some degree it isn't - travelling women don't often get murdered here - but New Zealand women do, most often in their homes.
"We can hold both these things as important as part of the vigil."
Vigils are also being held in Nelson, Christchurch and Dunedin tonight at 7pm.
Nationwide vigils for Grace Millane:
• 6pm Auckland, St Patrick's Square, off Wyndham St
• 7pm Auckland, Federal St
• 7pm New Plymouth, Puki Ariki Landing
• 7pm Wellington, Civic Square
• 7pm Nelson, 1903 Square
• 7pm Christchurch, Cathedral Square
• 7pm Dunedin, Octagon