Secret Tape Causes Chaos For New Zealand Opposition

New Zealand's opposition leader has apologised after being caught on tape using an expletive to describe one of his MPs, as police look into allegations about his handling of a political donations.

The recording features centre-right National Party leader Simon Bridges calling member Maureen Pugh "f***ing useless".

Bridges has this week been under sustained attack by a "rogue" MP within his own party who he had accused of leaking his expenses.

After earlier quitting during an extraordinary, hour-long press conference in which he heavily criticised Bridges, the former member for Botany, Jami-Lee Ross, on Wednesday laid a complaint with police.

He alleges Bridges had asked for a $100,000 political donation from a Chinese businessman to be divided up to avoid revealing its origin.

Bridges strongly denies any wrongdoing and says, while he had dinner with that businessman in May, the donations came from several supporters.

New Zealand's opposition leader Simon Bridges talks to reporters at Parliament in Wellington, New Zealand Wednesday, Oct. 17, 2018. Image: AAP

"[Ross] has defamed me and he is liar ... I have done absolutely nothing wrong," Bridges told reporters.

"There are a number of donations there from a number of individuals."

But Ross later on Wednesday also released a secret recording of a conversation he had with Bridges about the money.

And while it doesn't include any smoking gun or suggestion Bridges had asked for the money to be hidden, it caught him talking about replacing some of his MPs.

Simon Bridges apologising to reporters. Image: AAP

"Maureen Pugh's f***ing useless," Bridges is heard saying of National's 44th-ranking member.

He promptly apologised.

"I've apologised profusely to (Pugh) for my wrong comments. I am mortified. There's no excuse for them and they're entirely thoughtless. And they're not how I feel," he told reporters.

The tape also includes discussion about the ethnicities of potential MPs, with Bridges saying "two Chinese would be nice", but that risked creating a fight with current members.

Bridges later told reporters that while that comment was "blunt" there was nothing to apologise for.

"I am incredibly proud National is a party that thinks about multiculturalism and our representation," he said.

Police, meanwhile, in a statement said they were looking into the donation allegations to see if any further action needed to be taken.

Although National has been steady in the polls since last year's election, 42-year-old Mr Bridges has struggled to gain traction, sitting at 10 per cent in polling for preferred prime minister in August, compared to Prime Minister Jacinda Ardern at 40 per cent.