Simon Bridges will be worried facing MPs at caucus meeting - expert

National Party leader Simon Bridges will face his caucus for the first time on Tuesday since murmurs about a leadership challenge began before Easter, and a political expert says he will be worried.

Before the Easter break, MPs approached Newshub with concerns about Bridges' leadership abilities, with one saying the "numbers are firming for Judith [Collins] to lead the party".

On Monday, some of his MPs were frustrated with his handling of 'slushy-gate'; the criticism of Corrections for spending $1 million of slushy machines for staff.

"These people do a job that hardly anyone would. It smacks of bullying of staff that can't fight back," one told Newshub.

On Tuesday, Bridges will face those MPs for the first time since the recent murmurs, and Victoria University politics lecturer, Bryce Edwards, said he will feel concerned.

"Simon Bridges will be nervous going into the caucus meeting. I think every caucus meeting he's going to be going into he's going to be watching his back and thinking 'will there be some sort of kill against me this week'," he told Newshub.

He said Bridges may not be focussing on the right issues.

"He needs to focus on the big issues, things like tax, like the economy, like employment."

With the most recent Newshub-Reid Research also showing Collins having more support as preferred Prime Minister than Bridges, she is seen as the most likely successor.

But Edwards said they will only go with her if they want to take a risk.

"The National MPs want to be cautious and conservative and just careful they'll keep on with Simon Bridges. They want to take a risk, Judith Collins is the person. She's a lot better than Simon Bridges, but she's also a lot worse."

Newshub.