Former Prime Minister John Key says it is pragmatic for National leader Christopher Luxon to not rule out working with New Zealand First's Winston Peters, despite having done the same himself in the past.
Luxon said today that he would work with New Zealand First if the election results demanded it to form a government.
Sir John said it was a wise strategy by Luxon based on simple maths.
"The simple reality is you need 61 votes to form a government and I don't think anybody really knows how those numbers play out on election night," Sir John told Checkpoint.
"There's a very high expectation from New Zealanders that if you have the largest majority ... then you'll do everything you can to put together a government that stops the voters going back and having another election."
Recent polls have New Zealand First cracking the 5 percent threshold needed to get back into Parliament.
Key famously ruled Peters out as a coalition partner at two elections and NZ First has not gone with National into government in 27 years.
Luxon's announcement could be seen as a way of trying to ensure National and the ACT Party get enough votes to avoid New Zealand First being a factor.
"I think that he's absolutely saying that this is a change election and if you want the country heading in a different direction when it comes to law and order and the economy and health and education then you need to make that change. The best way to make that happen is for a strong National Party.
"Now in his perfect world ... that would be 51 percent.
"Do any of us think National's going to poll 51 percent on election night, probably not."
When Sir John ruled out Peters in previous elections, he said he didn't want to be involved in a "soap opera".
Asked if he thinks Peters has changed, Sir John said he did not know.
"But what I can tell you is this. Having had Labour rule him out ... if I was advising Christopher Luxon today about what he should do, I would advise him to rule Winston in under the conditions he's done.
"And the reason for that is that fundamentally if you got to Election Sunday, the day after the election, and the only alternative was another election because no one would ring Winston, I think the public would be pretty grumpy."
Sir John said he viewed Luxon's decision "as an attempt to be honest, if I'm really frank".
Ruling a party out does not mean they will not get the votes anyway, he noted.
"The problem you've got is that just because you rule them out doesn't mean that 5 percent of people don't vote for them.
The two big political parties, National and Labour, are not polling really big numbers, he said, which opens up the field for smaller parties to have more influence.
"The problem you've got is you've got a lot of vote splitting happening. And I don't think anyone can rule out that Winston doesn't get 5 percent."
Sir John said he talks to Luxon regularly but did not advise on this specific decision.
"Put it this way. I can count to 61. And whether you like it or not, politics is an ugly business, sometimes, and it's a race to 61."
Sir John did work with the then-Māori Party in partnership, but Luxon has himself ruled them out.
Sir John said he had good relationships with the party's then-leaders, but things have changed.
"I just think this current Māori Party are quite a different beast than they were in my day."
"I think this current Te Pāti Maori is a little bit different. ... I don't think they want to be part of that mainstream kind of thinking."
Sir John said he simply could not predict the election outcome, or whether Peters will once again be the kingmaker.
Sir John said working together could take many different forms.
“What happens if Winston becomes the speaker? In which case they’re technically not in government, are they?
“MMP requires a lot of creative thinking. Let’s say Winston was the speaker, then you only need 60 votes not 61, and maybe that’s the solution. I don’t know. … The trouble you have with MMP, it’s a beautiful thing to say here’s the outcome, and on that Saturday night or on that Sunday we’ll all be able to opine on that. But as it stands today I can’t make you a guarantee that Winston’s there or not there.
"Simple facts of life are, none of us are fortune tellers."
Labour's Chris Hipkins has ruled out working with Peters. If he changed his mind, it would be a disaster, Sir John thinks.
"That would be a terrible way to start a government, basically to lie to the New Zealand public."
Asked specifically whether or not people can trust Winston Peters, Sir John chuckled and said, "Hope so!"