NZ First leader Winston Peters is only talking to Labour and has said he does not want to be told what the Greens want out of a deal.

That puts the onus on Labour to form an arrangement with NZ First that will also be acceptable to the Greens.

Any arrangement will need to be approved by at least 75 per cent of Green members. This will be done through delegates.

Asked if he was confident Labour would represent fairly what the Green Party wants out of any deal, Shaw said he was.

"Jacinda made fairness one of her principle values in the campaign. I have known her for a number of years and I said this before the election - I trust her, and she seems to be doing a good job of it.

"It has got to be a stable and responsible Government that is going to go the full distance in the national interest. And Labour are working very hard in ensuring that happens. And that is of paramount concern to all of us. So I am very confident."

Shaw would not say if the Greens were considering or open to the idea of sitting on the cross benches, instead of being part of a Government with Labour and NZ First.

"I can't get into the detail of the negotiations."

Shaw said the Greens had campaigned hard to change the Government.

"That is what we campaigned on. We have thrown everything at it. That is what we are working on - is securing that deal to change the Government.

"It has got to be worth it for everybody."

Shaw said he wasn't concerned that Winston Peters had confirmed he wouldn't meet his self-imposed deadline of announcing NZ First's decision by tomorrow.

"I think a day here, a day there, is no big deal in the grand scheme of things. I'm pretty relaxed about the timeframe."

This morning, NZ First went into its first meeting of the day with National's negotiators for what is shaping up to be another long day of talks.

Peters' team included commerce, energy and trade spokesman Fletcher Tabuteau while National's included its trade and state owned enterprises spokesman Todd McClay. Both have previously been called into the talks a couple of times but are not constant participants - indicating a policy area they are involved in is up for discussion.

Otherwise NZ First's included Peters, Shane Jones, Ron Mark, Tracey Martin, Paul Carrad and a staff member. National's had English, Steven Joyce, Gerry Brownlee, Paula Bennett and chief of staff Wayne Eagleson. Jones has so far attended three meetings with National but has not been to any Labour meetings.

Peters and his team last met with National's team for just over an hour last night and it got the first billing again this morning - putting it two meetings ahead of Labour. That will even out slightly over the course of the day.

NZ First will meet with Labour at 12.30pm followed by a further meeting with National mid-afternoon. Then it is Labour's turn again at about 6.30pm. Peters has not ruled out squeezing in an extra meeting on top of those as he aims to close off discussions by tomorrow night.

Earlier this morning, Winston Peters left his office ahead of another round of the meeting.

Peters, accompanied by MP Shane Jones and adviser Paul Carrad, had little to say to waiting media.

"How can I possibly tell you how the meetings are going to go before the meetings start?"

Peters had said he would make his decision public tomorrow, but last night ruled that out, saying he expected decisions to go through until tomorrow night, and an announcement made as soon as possible after that.

Yesterday Peters pushed out his deadline for an announcement on which side he will back, and now says it will be made "as soon as possible after Thursday night".

He won't go as far as to confirm it will be on Friday.

"Our target is to complete all these discussions by Thursday night," he told reporters on Tuesday night after another round of negotiations with National and Labour.

"We will make it [the announcement] as soon as possible after Thursday night. I've got other arrangements and people to organise."

He apparently means a meeting of his party's board to ratify a decision. Mr Peters also said the timing depended on the other parties as well, but didn't explain what he meant by that.

If he decides to back Labour and the Greens, an issue could be ratification of the deal by a special meeting of Green Party members, which is one of that party's requirements.

Peters is still insisting that the decision is not his alone to make.

"Winston Peters is not going to make a decision - it is NZ First and it's board," he said.

"I can't speak for the party because I haven't had a chance to speak to them."