Judith Collins is being called out by her former chief press secretary for several recent outbursts including one against prominent microbiologist Siouxsie Wiles.
The National Party leader made comments about Dr Wiles after she was seen cycling to the beach, calling her a "big fat hypocrite".
Footage of Dr Wiles, who often gives expert advice on COVID-19, was reported last week by The BFD - a website run by ring-wing blogger Cameron Slater.
In an interview with The Spinoff's Fold podcast, Janet Wilson, who was Collins' chief press secretary during election 2020, slammed her former boss for what she says is "completely unacceptable for a National Party leader". "
"The fact that she is still working her bag of tricks with the likes of Cameron Slater shows us that she's learnt nothing since 2014."
Wilson described the National Party as being "on the brink of oblivion" - echoing comments made by lobbyist Matthew Hooton in a column last week. Hooton worked in Todd Muller's office during his brief stint as National leader last year.
She said the party hadn't changed since last year's election.
"In fact, what we have seen is more and more and more of the same. The party could politely be termed as being moribund," Wilson told The Fold.
"It is far too top-down. The board has far too many powers and makes far too many bad decisions, particularly when it comes to candidates.
"The article Matthew Hooton wrote for Metro recently talking about the fact that the party was on the brink of oblivion is entirely correct, entirely correct."
Collins' office has been contacted for a response to Wilson's comments. In an interview with The AM Show on Wednesday, Collins accused the media of turning "every little thing" she says "into a clickbait".
"Ultimately I'm here talking about the things that matter," she said.
"The thing is, is that if the media want to run those stories then they will. But I have to be able to do my job talking about the things that matter - such as the appalling vaccination rollout."
Collins went on to defend the comments she made about Dr Wiles.
"The fact is we've got someone who is constantly telling New Zealanders about staying home, not talking to your neighbours, keeping your mask on, and we had someone like her in a public place, clearly without a mask, clearly nowhere near where she lived and she's lecturing everybody."