Being part of a National-led Government is not an option for the three Green Party MPs contesting the co-leadership.

The fourth candidate, Vernon Tava - the only contender who is not an MP - says the Greens cannot afford to be "sitting on the sidelines" and wants to see the party at the centre of every government.

Tava along with Green MPs Kevin Hague, Gareth Hughes and James Shaw are bidding for the co-leader title after Russel Norman announced in January that he would be standing down at the party's annual meeting at the end of May, citing family reasons.



Shaw acknowledged at Sunday's co-leadership debate the power shift in Parliament since NZ First leader Winston Peters won the Northland by-election.

"The Green Party must grow otherwise the next Government will be decided by Winston Peters," he said.

"We can not continue with status quo - it's a path that leads to stagnation or decline."

While Hughes said he had a good relationship with Peters and NZ First MPs - he did not want the country being "reliant on NZ First to support a future government".

"Let's not be naive - relationships aren't going to change what's in NZ First's interests and if we're outside of that then we'll be outside of it."

He was campaigning on a "strong, independent Green Party that focuses on itself".

The debate at Queen's Wharf was the first in the capital and drew about 200 people. Candidate outlined their vision for the party, which was followed by a question and answer session.

It got off to a late-start due to Hughes having to seek medical attention after he stood on a nail walking home from the park with his children.

From there, talking points only seemed to get stranger as Hague took his five minutes of air time to talk about heading to space.

"Together we're building a rocketship to go to the moon," he told Green supporters.

"I know how to get to the moon. Trust me now, put on your space suits."

His astronomy-themed speech did not stop there.

When all four candidates were asked to choose someone - other than themselves, who they would like to win the co-leadership, Hague refused to pick a fellow contender and instead said he would like Neil Armstrong, an American astronaut and the first person to walk on the moon, to take it.

Tava was the only one prepared to tackle the question head on and opted to give his vote to Shaw "whether he wants the endorsement or not", he said.

The three MPs had made an agreement not to endorse any other candidate according to Shaw's dodging of the question and Hughes, the more seasoned politician, decided to exercise his right to not have to answer.