Winston Peters' decision: Poll too close to call

When it comes to picking who Winston Peters will side with, Kiwis are split right down the middle.

The NZ First leader is expected to announce who will form the next Government on Thursday afternoon, nearly a month after election day.

At the time of writing, an online Newshub poll had 52 percent picking he'll go with the Labour-Green bloc, and 48 percent with National.

Chris Trotter is in that slim majority, picking the veteran MP will choose to go out "with a bang, rather than a whimper".

"I cannot believe that the king is going to ride out of town leaving behind exactly the same story as 21 years before," the left-leaning political commentator and historian told The AM Show.

In New Zealand's first MMP election Mr Peters spent months deliberating, ultimately siding with National, his former party. The situation was remarkably similar to 2017 - National had the most seats, Labour second, with the left-wing Alliance (of which the Greens were a part) coming in fourth.

Mr Trotter says Mr Peters ultimately sided with National because "he couldn't get that rock-solid guarantee from the Alliance", which he hopes doesn't happen again.

PR consultant and former ACT staffer Trish Sherson thinks Mr Peters will again go with the biggest party, as he did in both 1996 and 2005 [when he sided with Labour].

"It's just the cleaner deal," she told The AM Show. "One of those great clichés is a leopard doesn't change his spots."

Winston Peters' legacy

Mr Trotter suspects National will gift Mr Peters, or his successor, a seat in order to get them onside.

"National can promise, more than Labour can, that they will make seats or a seat available to him. It's a guarantee, that survival of the party, which could be construed as a real legacy."

But Mr Trotter says it would be a poor one.

"ACT had what, seven? Nine MPs? Now it's reduced to a person who is there by the grace and favour of the National Party. If that's the legacy Winston wants, it's a pretty poor one."

Ms Sherson says it doesn't matter what National gives him - NZ First won't survive his retirement.

"If I'm really hand-on-heart about this, is New Zealand First really going to survive after Winston? No."

No losers

Both Mr Trotter and Ms Sherson suspect whoever Mr Peters shuns won't be held responsible for their party's loss.

"Both (Ms Ardern and Mr English) came out relatively well from the campaign, Bill particularly, and they'll go, 'Hey - actually, this might be a good thing,'" said Ms Sherson.

"Whoever Winston chooses to go with, this is going to be a three-year Government," said Mr Trotter.

"(Ms Ardern's) got time - more than what Bill's got - and that may well be a factor in what happens this afternoon."

Mr Peters told Newstalk ZB on Thursday morning the decision was yet to be finalised, despite the self-imposed deadline.