They have only been back at Parliament one day after their devastating defeat but already National MPs are leaking, telling Newshub they are predicting a coup. 

National leader Judith Collins obviously sees things differently and is planning to deliver a stern warning to leaking MPs at their first meeting on Tuesday. 

National's election campaign was a flop - in fact, an unmitigated disaster. But Collins says she gave it everything she could. 

The National Party leader told Newshub on Monday she gave it "absolutely everything I had and I think people understand that". 

Collins is also confident she'll stay on as leader until the next election in 2023. 

"I expect I will be."

But some of Collins' colleagues have different expectations. National's new and much smaller caucus meets for the first time on Tuesday and it will be brutal. 

National MPs have told Newshub:

• "We're going into a tough caucus and it will be a very full and frank post-mortem."
• Another says it is "highly, highly unlikely she'll [Judith Collins] lead us into 2023."

Collins says unhappy caucus members should let her know. 

"They better front-up and say who they are," she said. 

That's unlikely though, and some are saying who they think will have a go at the leadership, picking ex-Air New Zealand boss Christopher Luxon who has had his first day on the job after winning the Botany electorate.

• David Seymour's claim Labour turned $6b surplus into $1b deficit before COVID-19 'mostly true'
• But Ardern did lie...
• Advance NZ Party's Facebook page has been unpublished, it says
• FALSE PROFIT

Collins, when asked if she thinks Luxon will go for the leadership, said: "I don't know you better ask him."

Newshub asked Luxon and the messages were mixed. 

"Absolutely," he said, when asked if he could categorically rule out a leadership bid against Collins. "I'd like to get into Parliament and actually work out what I've actually got to do."

But Luxon didn't quite rule it out and didn't quite dampen talk of leadership ambition when asked if he was ignorant of the rumours of his leadership ambitions. 

"Well, I appreciate people may have expectations," he said. 

So, it's not personal ambition - other people want him to. 

Collins isn't fazed. 

"You couldn't get less worried than me," she said. 

Luxon said Collins can "absolutely" trust him. 

After National's massacre at the polls MPs are looking for scalps. There's fury from some directed at National MPs Nicola Willis and Chris Bishop who helped orchestrate Todd Muller's coup against Simon Bridges.

"Any blame game stuff is not going to be helpful," Collins said. 

But there will be a confronting forensic review of the party's litany of failures - leadership and leaks on the campaign included.

National's Tim Macindoe, who has lost his Hamilton West seat to Labour, said the MP who leaked to Newshub needs to "take a good, hard look at him or herself and either decide 'I'm going to become a good team player or I'll get out'". 

National's senior whip Barbara Kuriger said, "You know, people actually should say what they need to say in the room and keep it in the room."

And after more leaks sprung on Monday, Collins plans to deliver a warning to her caucus. 

"No party can win until it stops looking at itself."

Until then, leaders can't stop looking over their shoulder either.