The Public Service Commissioner Peter Hughes told ministers embattled public sector boss Rob Campbell failed to be politically neutral.
Newshub's obtained Hughes' advice. He told ministers Campbell had breached the code of conduct.
On Sunday, Campbell took to LinkedIn to criticise National's Three Waters policy, calling it "a thin disguise for the dog whistle on 'co-governance'".
That night Health Minister Ayesha Verrall wrote to Hughes raising concerns about the post and requested advice on the appropriateness of Campbell's comments and any action she could take.
"In my view, these comments are a breach of the Code and also demonstrate a failure to uphold the public service principle of political neutrality," Hughes told Verrall.
Hughes said he was aware concerns had previously been raised with Campbell about past public comments he'd made.
"These most recent posts are clear breaches of the Crown entity Board member Code of Conduct and also demonstrate a failure to uphold the Public Service principle of political neutrality and in my view compromise the trust and confidence he needs to operate effectively in this role."
Board members of public entities are bound by a Code of Conduct. One commitment is to be "politically impartial" and to avoid any political activity that could erode the public's trust in the entity
Parker only asked Hughes for advice on Wednesday morning - three days after Campbell's LinkedIn post and after he'd spoken at length to media defending his comments.
"It is for you to consider the matter in relation to Mr Campbell's role as the Board Chair of the Environmental Protection Agency," Hughes told Parker.
"In making that decision it is open to you to also consider the further public comments that Mr Campbell has made since Minister Verrall made her decision on this matter."
While the Commissioner provided advice, it was the ministers' decision and right under the Crown Entities Act to fire Campbell.
Campbell was fired as the chair of the Environmental Protection Authority (EPA) on Thursday.
It follows his sacking as Te Whatu Ora/HealthNZ chair on Tuesday after Campbell took to LinkedIn at the weekend to criticise National's Three Waters policy.
Parker said he accepted the Public Service Commissioner's advice that the post was a clear breach of the Code of Conduct public service bosses are bound by.
"Also, his subsequent public comments in the media suggest he does not accept the constraints he is under as a member and chair of a Crown Entity Board.
"That has eroded my trust and confidence in his ability to effectively undertake his role at the EPA."
Campbell told Newshub this week his comments were made in a private capacity and he didn't believe they would erode public trust in his ability to conduct his role.
"The code enjoins directors to be 'honest and open', to be 'fair' and to 'speak up'," he told Newshub after he was sacked from Te Whatu Ora.
"The code explicitly provides for a director to act in their 'private capacity', which I did. The limit on that is not to act in a way which 'could erode the public's trust in the entity'. There is no way my comments impacted Te Whatu Ora in that way."
Campbell has also claimed he had been the victim of a "witch hunt".
