As it happened: First leaders' debate - Bill English and Jacinda Ardern go head to head

• National leader Bill English and Labour leader Jacinda Ardern go head to head for the first time in a TVNZ 1 debate from 7pm.
• Listen live to the debate on Newstalk ZB and on iHeart Radio.
• Follow the NZ Herald live blog
• Check nzherald.co.nz after the debate for the wrap up and the verdicts

Voters got their first chance to see how new Labour leader Jacinda Ardern and the veteran National leader Bill English compared in a head to head election debate tonight - and the third player, moderator Mike Hosking, promised to deliver "balance up the wazoo."

The debate on TVNZ 1 came after polling showing Labour rapidly gaining on National - and both leaders had a lot to prove.

- Leaders Debate: The verdicts are in
- Kiwis react to first leaders' debate
- Shock poll: Labour leapfrogs National, Ardern leads English in preferred PM
- How Kiwi dollar reacted to shock poll
- Political Roundup: Tonight's leaders debate - who will be the real winner?

Ardern's challenge was holding her own on economic issues against the experienced English and defending the lack of clarity on Labour's future tax plans.

The debates are a chance to speak directly to voters and English's challenge was making sure Ardern does not push him into the shadows - and trying to resonate with those voters rather than numbing them with numbers and statistics.

Ardern spent most of the day and yesterday afternoon rehearsing for the debate. She admitted to some nerves on Mike Hosking's ZB show this morning.

"I would be superhuman if I didn't have nerves. I would think both of us would be nervous."

She said it was hard to prepare for. "You've just got to be yourself, you've got to make sure you've got a clear idea in your head of what you want people to walk away from the debate having heard from you about."

English also spent much of the afternoon preparing after a homelessness announcement and walkabouts in New Lynn and then Kumeu.

He said it was up to voters to decide how the two compared.

Asked what his style was if Ardern's was self-proclaimed "relentless positivity," he said his would be "getting things done".

"Our main focus has been not so much on the theatre of the debate, it's around the substance of the policy that this Government is rolling out."

English and Ardern will not be the only ones under scrutiny - there has been controversy over TVNZ's decision to choose Mike Hosking as the moderator again this year, including a petition calling on him to be replaced.

Ardern joked her appearance on Hosking's ZB show was a "trial run" - and after he asked what outfit she would be wearing, she said she expected him to ask the same question of English.

"There'll be balance up the wazoo," Hosking reassured her.

There was a similar controversy last election when then Labour leader David Cunliffe initially objected to Hosking. After the debate he said he'd had no concerns with the way it was moderated.