Now that Russel Norman has announced he will stand down as Green Party co-leader, the party faces the challenge of finding his replacement.
What is the process from here?
Nominations for a new co-leader will open on 20 March and will close almost a month later.
Nine "meet the candidates" hui will be held around the country in the last two weeks of April.
An election will then be held at the Green Party's AGM which is on 30 May and 31 May.
Who are the possible candidates?
The Green Party's constitution requires both a male and female co-leader.
Any financial member of the Green Party can apply for the job, which means a non-MP could feasibly run for the position, as Dr Norman did successfully in 2006.
Dr Norman was co-leader outside Parliament for about two years before being elected in 2008.
However, the contenders are most likely to come from within the caucus.
The six other male Green MPs are: Steffan Browning, David Clendon, Kennedy Graham, Kevin Hague, Gareth Hughes and James Shaw.
The two most likely candidates are Kevin Hague and James Shaw.
Kevin Hague - is in third place on the party's list, behind Metiria Turei and Russel Norman. He was first elected to elected to Parliament in 2008 and is the party's health and housing spokesperson.
Mr Hague previously held senior roles in the health sector, including as director of the AIDS Foundation and chief executive of the West Coast District Health Board.
He declined to say whether he would throw his hat in the ring, saying that would not be appropriate at this stage.
"I would anticipate that there'll be a keenly contested process for choosing a successor," he said.
James Shaw - is the Green Party's newest MP, coming in on the list at number 13 in September's election. However, he has long been discussed as having the nous to one day lead the party.
The Wellington-based MP, who previously worked a business consultant, is the party's spokesperson on economic development and justice.
He issued a statement after Dr Norman's resignation, thanking him for his "extraordinary" contribution.
"The election of a new co-leader is several months away. The party is stronger than it has ever been before and has many members with strong leadership abilities.
"Today is one to celebrate Russel's great contribution and that's where the focus should be," he said.
David Clendon - is an outside possibility as a contender. He's number 11 on the Greens' list and ran for the job in 2006, when Dr Norman was successful.
Mr Clendon lives in Auckland and is the Greens' police and corrections spokesperson.
"At this point I've made no firm decision... 2015 is a very different environment [from 2006]... I'll make a decision quite soon."