Christopher Luxon is calling for Prime Minister Chris Hipkins to undertake a review into all conduct by Stuart Nash in his time as a Minister.
Hipkins sacked Nash on Tuesday evening from his ministerial positions.
In 2020, Nash emailed business figures about his disappointment at a Cabinet decision on a commercial rent relief package. Two recipients of the email were Troy Bowker and Greg Loveridge, who have both donated to Nash. They are also commercial property owners who had an interest in the Cabinet decision.
The National Party leader told AM on Wednesday he'd like to see Hipkins undertake a review to make sure Nash hasn't leaked anything else.
"You do end up asking the questions, well, what else has been shared? Think about the portfolios that Stuart Nash has had around economic development, forestry and fisheries," Luxon told AM co-host Melissa Chan-Green.
"I think Chris Hipkins has to undertake some sort of review and reassure himself that no other information has been leaked or to others."
Luxon said the leaking of confidential Cabinet discussions with his donors was "egregious" and called for him to leave the Beehive now.
"What we've seen is a really serious and egregious contravention of the Cabinet manual. We haven't actually seen something like this before in New Zealand," Luxon said.
"The question for me is, if he's lost confidence in him in Cabinet, how has he not lost confidence with him being in caucus."
It's now up to Nash to decide himself if he wants to leave the Beehive. If he does so after April 14th - it won't trigger a by-election for his Napier seat.
But it seems like Nash won't leave his Napier seat after telling RNZ "there will be no by-election".
Even if Nash decides to stay in his Napier seat, National still can force a by-election within six months of an election.
The House has to resolve not to have a by-election and a motion has to pass with 75 percent support for a by-election to not happen, according to the Electoral Commission.
"I want to see what Chris Hipkins is going to do today. I don't understand how he comes out and makes really strong statements about why he can't trust Stuart Nash in Cabinet, but now he's saying that he can accept having him in his caucus," he told AM.
"I'm less hung up on the by-election, I get it it's an inconvenience and people want to avoid that, but I don't understand how you say we're going to just sit there for six months with an issue that's about behaviour and about standards in a country that prides itself on its reputation globally."
Luxon said it doesn't seem right for Nash to "stick around" just to avoid a by-election and is calling for a principles-based conversation.
"I guess the sad and frustrating thing is we've now got a Government six years into power that's so internally focused," he said.
"Every week I come before you and we talk about Labour Government personnel issues. It ranges from former cabinet ministers not reading codes of conduct and governance roles of crown entities and ministers not reading cabinet manuals."
When pressed by Chan-Green about National having its own issues, like the Sam Uffindell saga, Luxon said they've had nothing like this.
"Nothing like this. I can't think of an incident where a Cabinet Minister has actually gone into a cabinet meeting and leaked information to his donors about an issue that they are interested in," Luxon said.
Watch the full interview with Christopher Luxon in the video above.
