Duncan Garner has called on Simon Bridges to step down as National leader, after an explosive week in politics that saw ex-National MP Jami-Lee Ross accuse his former boss of corruption.
"He is not so much dead-man-walking but dead-man stumbling in the dark, surrounded by a giant snake with a killer bite that multiplies by the second," Garner said, referring to Mr Ross' revelations about Mr Bridges.
"You have sadly, seen the very worst and dark side of politics play out this week," Garner told The AM Show.
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The former Botany MP released audio tapes to police and to the public on Wednesday, alleging Mr Bridges engaged in electoral fraud. The recording shows Mr Bridges discussed what to do with a $100,000 donation from Chinese businessman Zhang Yikun.
Mr Ross alleges Mr Bridges later asked him to divide it into smaller amounts to hide it from the Electoral Commission. He says it was on May 21 that Mr Bridges told him to split it up the donation, but admits he has no clear evidence of this.
"Simon has lost control, and lost control of what he might say next in the public arena," Garner told The AM Show on Thursday. "Everything is now designed for maximum embarrassment and public humiliation."
Mr Bridges can also be heard on the recording talking about one of the Chinese donors possibly becoming a party candidate and going through "candidate college". But he said on Wednesday that if Mr Zhang thought his donation would buy a candidacy, he "categorically did not get that from me".
"It is untenable for Bridges to continue," Garner told The AM Show. "National needs to lance this gigantic boil before the weekend."
Mr Bridges also apologised to members of his party after the recording Mr Ross released on Wednesday revealed Mr Bridges mocked several National MPs and called list MP Maureen Pugh "f*king useless".
Soon after the audio was released on Wednesday afternoon, Mr Bridges announced he'd met with Ms Pugh to apologise in person. Ms Pugh's mother has since come to her daughter's defence, calling Mr Bridges a "dumb arse".
"Decent, ordinary, hard-working Kiwis simply can't be bothered with this mongrel dog approach where you must keep your friends close and your enemies even closer," Garner added.
"For his own sake, and for the sake of his party, he must step down as leader."