Winston Peters in touch with both English, Ardern

Winston Peters is in touch with both caretaker Prime Minister Bill English and Labour leader Jacinda Ardern.

Nine days on from election night, the kingmaker has finally spoken to both of the major parties.

Mr English said on Monday morning he rang the NZ First leader at the weekend, "but he wasn't answering the phone".

"I think he's sticking to the plan that says he's not going to talk to anyone until probably next weekend after the specials," the National leader told The AM Show.

A spokesperson for Ms Ardern, who's looking to form a three-way coalition between Labour, NZ First and the Greens, confirmed to Newshub she has also been in touch with Mr Peters.

Discussions between the two parties are expected to begin later this week.

Missed call

Reports earlier on Monday suggested Mr Peters didn't realise Mr English had called before it was too late on Sunday evening, so was going to call back Monday morning. Mr Peters has since said that was false, saying in a statement he "has already responded to Mr English by phone".

"Preliminary talks will proceed this week when arrangements suitable to both parties are concluded," Mr Peters explained, contradicting previous suggestions he wouldn't talk until October 7, when the election results are confirmed and the special votes counted.

Mr English doesn't think it will make much difference, even if National "dropped a seat or two", as is expected.

"We've still got the most seats by quite a long way."

Mr Peters has promised his mind will be made up by October 12, when the results of the election are formally presented to the Governor-General, but Mr English has his doubts.

National has formed the last three Governments with the same coalition partners - United Future, the Maori Party and ACT - and even then, Mr English says discussions took weeks. The difference is, they started negotiations on election night, not two weeks afterwards.

"New Zealand First has got a big challenge - they've got to negotiate with two other parties on the other side of this - the Greens and Labour - just with us on our side of it. It's quite a complicated process," Mr English said.

"By the time you work through the policy issues, get the detailed wording right, get agreement… and then get it all formally signed up, we certainly never got through that in four or five days."

What about the #TealDeal?

He hasn't called the Greens yet, saying they appear "fairly determined" not to do a deal. Leader James Shaw suggested otherwise at the weekend, saying he'd "hear the Prime Minister out" should he call.

"I'm keen for the Greens to have a chance at Government, because we've never really had that full opportunity before," Mr Shaw told RadioLIVE's Rural Exchange show.

"All of those things are theoretically possible," Mr English said. "That's a matter for them. It does look like it'll be quite a stretch for them."

He called Mr Peters first because Mr Peters hasn't played any of his cards, while the Greens have quite openly said they'd rather form a Government with Labour.