Metiria Turei has resigned as co-leader of the Greens, dealing her party another blow just as an opinion poll shows Labour surging up the ratings.
The Greens were trying to get their election campaign back on track after two senior MPs, Kennedy Graham and David Clendon, on Tuesday withdrew from the caucus.
They wanted Ms Turei to stand down because of her admission that she committed benefit fraud in the 1990s, but she insisted on staying.
All that changed around 5pm on Wednesday when Ms Turei and the party's other co-leader, James Shaw, called a media conference.
"I knew that by telling my personal story, it would help people hear and understand the reality of poverty," Ms Turei said.
"And that has happened - thousands of people have contacted the Green Party with their stories, and many have come forward to tell these in the media as well.
"I also knew that it would open the way for people to criticise me - and I knew the risks of that - but the intensity of those attacks has become too much for my family, and they are now getting in the way of our ability to communicate our solutions - not just for poverty, but for water, climate change and the environment."
The poll showed the Greens taking a hammering - down 4.7 points to 8.3 per cent - but Ms Turei said it wasn't a factor in her decision to stand down.
It also showed Labour up a stunning nine points to 33.1 per cent and the party's new leader Jacinda Ardern, snapping at Bill English's heels as preferred prime minister.
She was on 26.3 per cent compared with Mr English's 27.7.
NZ First was down in the poll, losing 3.8 points to be on 8.3 per cent - another casualty of Labour's big surge.
Mr Shaw will lead the Greens into the election as its only leader, with a new co-leader chosen post-election.
Dr Graham and Mr Clendon won't be returning to caucus.
Ms Turei has been on a downward track since making her admission, which she says she did to highlight the plight of beneficiaries.
While gaining some sympathy within parliament, she has also been fiercely criticised and last week Labour leader Jacinda Ardern said she wouldn't have Ms Turei in her cabinet if Labour won the election.