Greens co-leader Russel Norman is facing a challenge for the party leadership from a low-ranking Greens candidate.
David Hay, who is 16th on the Greens' list, said Dr Norman had done a great job but he had been co-leader for six years and a change was needed.
It is the first time Dr Norman has been challenged for the top spot.
In a statement released this morning, Mr Hay said: "There is a real possibility that the Greens will be in government after the next election, and the party needs to be putting its 'A' team forward."
Mr Hay, a policy analyst at the Auckland Council, said the party had too few MPs in Auckland and one of its leaders should be based there.
"The Green Party has under-performed at winning votes in Auckland, and we need to turn that around.
"Only three members of the Green Party's 14 MPs are based in Auckland. We currently lack sufficient presence here, in New Zealand's largest city, where a third of the population live."
Mr Hay was the Greens' candidate in Epsom in the 2011 election and won 12 per cent of the vote. He also stood in Rodney in 2008.
Green Party members would vote on the leadership at the annual general meeting in June.
Dr Norman said he was "very confident" he would be re-elected because the party was doing very well.
In 2006, he was chosen as male co-leader ahead of Nandor Tanczos, Mike Ward and David Clendon.