Prime Minister Jacinda Ardern says National Leader Simon Bridges' decision to rule out working with NZ First after the election is just "electioneering".
But speaking to media this afternoon, Ardern was loathe to comment much on the development, saying only: "We're getting on with governing New Zealand".
She said the Government was focused on the response to the coronavirus and other important issues – "everything else I consider electioneering and I won't spend time on it today".
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NZ First Leader Winston Peters, who was with Ardern, also refused to elaborate much on National's decision, telling reporters it was "not important" at this point in time.
In an earlier statement, he said he was "unfazed" by the decision and said Bridges had "a lot to learn about politics".
But, after being pressed, Peters revealed that he wrote the statement criticising Bridges three hours before the National leader fronted to media, "knowing typically how some people who don't understand this game, would behave".
Bridges made the much-anticipated announcement at National's annual retreat at Havelock North this afternoon.
He has always said he would make any future potential coalition partner decisions in early 2020.
"I don't believe we can work with NZ First and have a constructive, trusting relationship," he said.
He added that he could not trust NZ First and would rather be in opposition for another three years than form a Government with the party.
New Zealanders, he said, were sick of the "charade" with NZ First and National wanted to give Kiwis a clear choice before the election.
"Our decisions will be about what's best for New Zealanders, not what's best for NZ First."
Bridges' move echoes former Prime Minister John Key's move in 2008 and 2011 to rule out NZ First - and in 2008 it was one of the factors that got NZ First removed from Parliament.
If NZ First does not get above 5 per cent, and fails to win an electorate seat, the party will not get back into Parliament.
Bridges would not be drawn as to whether this was part of his thinking.
In his statement, Peters was critical of Bridges and his leadership.
"Narrowing your options can be the worst strategic move you will ever make," he said.
"If Mr Bridges doesn't pick up the phone, someone else within his caucus will do it for him."
Peters said that he had been in politics a long time and has been a member of both NZ First and National.
"The one thing New Zealand First is confident about is that if voters deliver that possibility [of forming a Government], and if Mr Bridges doesn't pick up the phone, someone else within his caucus will do it for him."
Peters said Bridges had also demonstrated he has no insight into what a unified caucus looks like.
"As Douglas McArthur said; 'there'll come a time soon when he'll when want to see me much more than I want to see him.'"