Green Party leader James Shaw wants a ministerial economic role in any Labour-Green government, he has told Morning Report's Guyon Espiner.
Watch the interview - part of RNZ's in-depth election series - here:
The latest poll averages show the Greens just over the level of support needed to stay in Parliament.
Mr Shaw declined to say what specific job he would like in a potential Labour-Green government but said it would be a ministerial economic role, and the party would seek portfolios for other MPs.
"The roles that we are going to be looking for are roles that mean we can clean up all of our rivers, that we can have a real crack at ending poverty in this country once and for all, and that we can make New Zealand carbon neutral by the year 2050."
The party faced a tumultuous period in July, when Metiria Turei resigned as co-leader over her admission of benefit fraud and two senior MPs rebelled.
Mr Shaw said Mrs Turei's admission "didn't work out as well as we would have liked it to" and she was unfairly treated by parts of the media, but he was now focused on the election.
"Right now I cannot spend that much time looking in the rear view mirror.
"We've got an election to win and the polls are starting to show it is very very tight, very close."
He disagreed with Labour Party president Nigel Haworth's comments that it was "simply wrong" to say a Green vote was a strategic vote for a progressive government. But Mr Haworth was doing everything he could to drive up the party vote, he said, and the Greens needed to do the same thing.
Mr Shaw said Labour had more ambition than National to solve the "greatest challenges of our time" and the Greens had a key role in that.
On climate change, Labour had signed up to net zero emissions, but would not commit to a ban on deep sea oil drilling or new coal mines.
"This is why you need the Green Party to be at the heart of that government, because you cannot say you are serious about climate change and making New Zealand a net zero carbon economy if at the same time you're also committed to opening up new coal mine or new oil drilling."
Though both National and Labour had goals on lifting children out of poverty, Labour was more likely to push those policies over the line, he said. "What the National Party is saying is that they're going to do a little bit, they're going to poke at the problem, they're not committed to actually fixing it."
Labour has ruled out changes to personal income tax rates, while the Greens were going into the election with proposals including raising the top income tax rate to 40 percent.
"We would like to see this tax switch that we're talking about, but it is one of a number of policies that we're taking into the election and we'll just have to see what the outcome of the election is," Mr Shaw said.