As National MPs rally behind Simon Bridges in the wake of Jami-Lee Ross' explosive accusations, political experts believe that Bridges' leadership is safe - for now.

The unprecedented events this week have seen the leader try to keep the caucus unified as he apologised for calling Maureen Pugh "f***ing useless", and faced allegations of electoral fraud and a cash-for-candidates scheme.

Bridges denied any wrongdoing and welcomed a police investigation. He hit back, calling Ross a leaker and a liar amid allegations that Ross had acted inappropriately towards women.

National MPs have thrown their support behind Bridges, with Chris Bishop saying he had done an "outstanding job" and Jacqui Dean saying the team were "100 per cent" behind him.

Advertisement

Victoria University politics lecturer Dr Bryce Edwards said Bridges' performance in his Tuesday press conference lead to an impression that he may not last the week.

"He seemed evasive and was on the back foot, didn't really come across as confident or ready to give answers, and that's often how politicians look when they're about to fall," Edwards said.

"I thought he couldn't survive."

But after Bridges' fronted media on Wednesday - following the release of the recording where he and Ross talked about pushing out some current MPs, such as Pugh - Edwards changed his mind.

"He rose to the occasion and came out kicking. The caution dropped away and he had a sense of authenticity. He sounded like he was fighting back and it stemmed the tide calling for Bridges to stand down."

Former National Party press secretary Ben Thomas said Ross was the clear villain in the eyes of the National caucus, which has rallied behind Bridges.

"When Ross releases a tape of mean-spirited comments about Maureen Pugh, no one is under the illusion that he's doing that to defend Maureen Pugh's honour. He's doing that to humiliate her and the leader. That has brought the caucus together.

"If all that's coming is more secretly taped gossip, innuendo, or off-hand comments, I don't think that will be a problem for Bridges' leadership. All MPs recognise that the villain is Jami-Lee Ross, and he has failed to show us a smoking gun or any compelling evidence of criminal or political wrongdoing."

Thomas said the events of last week gave more credence to Bridges' decision to push ahead with a leak inquiry - something he was heavily criticised for - as an attempt to deal with a rogue MP.

He said the allegations of inappropriate conduct towards women also provide context for Bridges' use of the term "embarrassing" when describing the reason for Ross' leave, and explain deputy leader Paula Bennett's comments about Ross' inappropriate behaviour for a married MP.

"People thought they were being unfair to Ross. What we've learned since is that that wasn't the case at all."

Thomas said a more serious issue for the party was whether there was any cover-up over Ross' alleged misconduct with women.

"And it doesn't seem like any of that happened while Bridges was leader, so that wouldn't be a threat to his leadership, though it could be a problem for senior figures on the party board."

Thomas did not expect Bridges' leadership to be under threat in the immediate future.

"It's probably inevitable National will take a hit in the next poll. It's very untidy and people just see a mess. But I don't think his colleagues will blame Bridges in the short-term."

He said there were always ambitious MPs who might mount a leadership challenge.

"But if the caucus can be relied on to act on their best interests, Simon Bridges - barring any further revelations - should be the leader in the 2020 election."

Edwards said he still thought Bridges might be ousted as leader before the 2020 election because of what Ross might still have up his sleeve. The fact he is being advised by Simon Lusk, who advertises himself as someone who can remove politicians, shows that the saga is far from over.

"We're in such an unpredictable scandal with so many unknowables, and Lusk has to be taken seriously."