Green Party co-leader Russel Norman has had his leadership challenged by a low-ranking candidate.
David Hay, who is 16th on the Greens list, says Dr Norman had done a great job but it was time for a change.
Hay, a policy analyst at Auckland Council, said in a press release published on Scoop this morning that the party had too few MPs in the city, and that one of its leaders should be based there.
He was the party's candidate in Epsom in the 2011 election and won 12 per cent of the vote.
Green Party members would vote on the leadership at the annual general meeting in June.
Dr Norman told Radio New Zealand's Checkpoint programme on Wednesday evening he was confident that he would be re-elected.
Dr Norman was elected in 2006 ahead of Nandor Tanczos, Mike Ward and David Clendon.
Commentators on Twitter were quick to remark on Hay's announcement with the hashtag "#greenspill".