Election 2020: National campaign reviewer to leaking MPs - 'pipe down'

The mastermind behind a run of successful National Party campaigns today fired a broadside at trouble-making politicians warning them to "stop talking out of school".

Speaking to NewstalkZB's Mike Hosking, former cabinet minister and party strategist Steven Joyce said Saturday's disappointing result for National had no doubt left many smarting but it was a time for introspection.

Pinpointing National's demise back to the events in 2018 that saw renegade MP Jami-Lee Ross expelled from the party, Joyce said the re-elected caucus needed to learn from mistakes and focus on getting back to Parliament in greater numbers in three years' time.

He warned now was not the time for rolling the leader but coming together as a cohesive unit, and that meant bringing an end to leaks that had proved damaging in the lead-up to polling day.

"I don't think there should be any change. I think Judith has done a good job. By her own admission she says it hasn't been perfect - it's very hard for it to be in that situation.

"I think it's really important that people stop talking out of school," he said.

He was certain members of the National caucus would know the identity of the leakers and it was up to them to rein them in.

While there appeared to be no political factions within the National party he revealed there were personalities that threatened to pose problems.

"The factions are personality factions and there are a few personalities who think they should run the show and they would have done a hell of a lot better," said Joyce.

"I've got news for them - they probably wouldn't have."

This morning National MP Mark Mitchell, who previously had a tilt at the leadership, gave his unqualified backing to Collins saying his dreams of being the leader were buried.

"We're not focused on any change in leadership, we're one hundred per cent behind the leader, we've got a lot of other work to do and other things to focus on and that is namely getting organised, getting back into Parliament and holding the government to account," he said.

He told Mike Hosking it would be a difficult day in the caucus room with 20 politicians losing their jobs at the weekend.

"It's going to be a very sombre mood today without a doubt because we're going to farewell 20 of our colleagues."

But now more than ever was the time to have united caucus.

"We just had a really tough three years really and it's a chance for us to reset and do our job as an Opposition."

He said the National Party would be working closely with Act in the next Parliament to provide a strong Opposition.