Green Party leader James Shaw says this election is going to be the "fight of my life, absolutely" after a drop in the polls following Metiria Turei's resignation.
The latest RNZ Poll of Polls, which is an average of the most recent major polls and includes last night's 1 News Colmar Brunton result, has the Greens on 6.9 percent, down from 13.5 percent.
It has Labour on 35.5 percent, National at 43.7 and New Zealand First at 9.1 percent.
Last night's Colmar Brunton poll showed the Greens dropping from 15 percent to 4 percent, which would be below the threshold required for the party to re-enter Parliament without an electorate seat.
Mr Shaw, now the solo leader of the party, said the result was expected and was adamant the Greens could turn things around before next month's general election.
"This is as low as we're ever going to go, this is rock bottom for us," Mr Shaw told Morning Report.
"To be honest with you I'm not hugely surprised. We knew that we were going to have a string of bad polls because of the messiness of the last couple of weeks and because of what everyone is calling the Jacinda effect," he said.
"But, I know we will be able to rebuild, and that is my job over the course of the next few weeks."
The first rule of New Zealand politics was that voters hated seeing the kind of mess that the Green Party had faced in recent weeks, he said. It was now his job to "steady the ship".
"They also need to know that the way that I see my job is rebuilding that trust and that credibility and to fight to earn the respect and the votes of everyone in New Zealand over the next five weeks ... What happened over the last few weeks is an aberration."
He said the party's own internal polling currently put it somewhere between 8 and 9 percent. He repeated his belief the party would return to its historical average, about 10 or 11 percent.
'Greens do best when their backs are against the wall'
Former Green party co-leader Jeanette Fitzsimons was also confident the party could improve its standings before the election.
Last night's poll was just one result, she told Morning Report, and there was still a lot of campaigning to be done before 23 September.
When the Greens fall on hard times, they pulled together and worked harder, she said.
"Greens do best when their backs are against the wall. It will galvanise the workers; it'll be a wake-up call for those campaigning to get our there and clarify the issues.
"The policies are good, so I have no doubt at all that we will come back up again."
Ms Fitzsimons said she would advise the party against trying to cut deals with Labour over electorate seats to ensure they have MPs after the election.