Rob Campbell's witch hunt accusations are 'nonsense', political expert Bryce Edwards says

A political expert has laid into now-former Te Whatu Ora/Health New Zealand chair Rob Campbell's accusations he is the victim of a witch hunt, labelling the claims "nonsense".

Health Minister Ayesha Verrall sacked Campbell from the public sector position earlier this week after the fallout from comments he made on social media criticising the National Party's alternative Three Waters policy.

Public servants are required to be politically neutral in their roles.

But Campbell said he had no regrets about the comments and believed he was being publicly targeted.

"It feels even a little bit like a witch hunt which is, again, a dramatic phrase," he told Newshub on Wednesday. 

Political scientist Bryce Edwards, from Victoria University, told AM Early on Thursday those accusations were "nonsense".

"It shows why he was always an unsuitable person for this role - he doesn't understand the important rules that New Zealand has in our constitution… that doesn't allow public servants to be as partisan as he wants to be," Dr Edwards told host Nicky Styris.

"He just clearly doesn't have the judgment and the idea that he's been the victim of some sort of witch hunt is really quite extraordinary, and he just keeps on doubling down and showing that the Government really did get it right in sacking him."

Campbell was also expected to be sacked from his role with the Environmental Protection Authority.

Prime Minister Chris Hipkins said on Wednesday he understood Campbell was "having conversations with the Minister for the Environment today… Clearly, there are processes that need to be followed".

Because Environment Minister David Parker is also the Attorney-General, his process had to be more thorough than Dr Verrall's.

Dr Edwards said a political public service could result in distrust.

"It really brings great big questions for the public service," he said. "It reduces confidence in them - it makes them look like they're just part of the political machine."

He believed that's not what New Zealanders wanted.

"What we don't want is we don't want our public sector to be part of the 'electoral weaponry' of the politicians," Dr Edwards said. 

"We don't want them to be trying to be get a Government re-elected or whatever, we just want them to be delivering things, to be neutral and reliable and so that when we have a change of Government, we don't have top change all the machinery.

"[Campbell] really has crossed that line."