Green Party co-founder and former leader Jeanette Fitzsimons still wants the party to pull their support for the Waka Jumping bill – but says she has hit a "brick wall".

Former MP Sue Bradford told The Nation this morning she wanted this weekend's annual Green Party conference to pass a motion forbidding the party from backing the bill.

The Green MPs are still planning to reluctantly vote for the Waka Jumping bill at third reading. The bill would allow party leaders to banish MPs from Parliament if two thirds of the caucus agreed they should go.

The Green Party have historically campaigned against such bills but say their Confidence and Supply agreement with Labour forces them to vote for the bill, despite the fact the law is not mentioned in that agreement but is instead part of the coalition agreement between Labour and NZ First.

Fitzsimons has made her opposition to the bill clear in the past. She said it would "be great" if the conference passed a motion forbidding the MPs from supporting the bill, but she didn't think this was likely.

"It would be great if [a motion was passed] but I think we have tried everything we can try and we have been met by a brick wall. I think we have to move on."

"I'm disappointed in that decision that was made but I'm not going to dwell on it for the rest of my life," Fitzsimons said.

Fitzsimons said there were tensions to be worked through at the conference, but she was proud of the work the party had done so far in Government.

SUPPLIED Green Party co-leader James Shaw and Marama Davidson at his party's annual conference. Shaw said the rule change was about how the party operated as part of an MMP government.

RULE CHANGES AT CONFERENCE

​Fitzsimons was more disappointed about a rule change to the way MPs were bound by the decisions of the wider party, but wouldn't elaborate further on that change as it was not yet public.

It wasn't clear exactly what that rule change was. Asked if she was disappointed in the caucus decision to support Waka Jumping, Fitzsimons said "I'm more disappointed in the fact the party rules were changed to mean that we can now do that legitimately any time we want to, I think that is much more serious."

Party co-leaders James Shaw and Marama Davidson said they were simply reviewing all of the party's "documents" including the constitution – but weren't necessarily freeing MPs to act in ways the membership didn't like.

"We've got an agreement with the caucus and the party about how we communicate with each other, and so we've always had that, but we're reviewing that in light of what it means to be a Government," Shaw said.

"It's essentially about how we can operate as part of an MMP government, and how we can square the circle of making sure you stick to your policy however you can, maintain your vision and kaupapa, and provide a stable Government."

The current constitution mandates near-constant coordination between MPs and the membership executive.

Fitzsimons said the party had to be careful about tradeoffs on issues like Waka Jumping.

"You have to be really careful about tradeoffs – that you don't trade off core principles against policy gains are of a different nature."

"The opposition to the party hopping bill now is because it's wrong. It's because it denies MPs basic freedom of speech, freedom of association, freedom of thought – it's contrary to the bill of rights and to our policy."

Fitzsimons doesn't believe the Government would fall apart if the Greens pulled their support for the bill.

"I simply don't buy the line that Jacinda [Ardern] and [Winston] Peters would say 'oh we don't want to be Government any more so let's let it all collapse because we didn't get this bill through.' I mean really?"