Green MP Kevin Hague could have competition for the party's leadership as two more MPs have tentatively suggested they might enter the contest.
MPs Gareth Hughes and Kennedy Graham would not rule out bids for the male co-leadership position, which will be up for grabs when Russel Norman stands down in May after eight years.
Mr Hughes confirmed yesterday he was consulting with supporters about whether he should enter the race, but said he would not confirm his intentions until closer to the nomination deadline in mid-April.
He is ranked fifth on the party's list and has gained some profile in lobbying for environmental causes.
Dr Graham, who is one of the party's senior MPs and speaks for the party on foreign affairs, said he "had not discounted the idea" of entering the leadership race.
Third-ranked MP Kevin Hague last week confirmed his intention to seek the co-leadership, and was likely to be the front-runner for the job.
First-term MP James Shaw was also considering a bid for the job, but has said it is "highly unlikely".
Mr Shaw has been tipped as a future leader of the party but is wary of his lack of experience after only five months as an MP.
It is understood that a candidate outside of Parliament may also enter the contest in an attempt to raise their profile.
Nominations for the leadership close on April 17, and after a series of public meetings across the country, Green delegates will vote on the new co-leader at the party's annual general meeting in late May.