Jacinda Ardern's partner Clarke Gayford has been under an unprecedented assault of baseless rumour and false innuendo with the apparent intent of dragging down the Prime Minister.

For the past seven months, Gayford has been the subject - on social media and via word of mouth - of untrue allegations and accusations.

The sheer scale and nature of the claims have led to Police Commissioner Mike Bush taking the extraordinary step of signing off a media release that rejects the speculation.

The Police National Headquarters statement said: "While in general we do not respond to enquiries which seek to confirm if individuals are under police investigation, on this occasion we can say that Mr Gayford is not and has not been the subject of any police inquiry, nor has he been charged in relation to any matter."

READ MORE: 
Opinion: Low-life gossipers a distraction for PM's office
Clarke Gayford rumours labelled 'dirty politics'

Exhaustive inquiries by the Herald have found no substance to the false rumours.

Gayford said he did not want to comment.

The Prime Minister told the Herald: "I won't comment on dirty politics. It's just not what I'm here for."

The Herald and Newstalk ZB have in recent months received many "tips" reporting variations of the speculation. The false rumours have also travelled by word-of-mouth through business, legal, media, political and social circles - and have been published on social media platforms.

One of those who published material on social media did not respond to a request for comment. The other said he did not monitor comments on posts because it was too time consuming. He was unaware such allegations had been made in comments on his posts.

He said morally and legally a person could not be held accountable "for something on a forum for something they did not see".

But he said he had an obligation, once alerted to improper comment, to take action and would remove defamatory or offensive comments.

He was aware of the false rumours, he said.

"Every person who has talked to me about the rumours, I've said 'it's a myth'. I've done nothing but push back against them."

The untrue rumours about Gayford have also been published on Twitter.

Media commentator and Public Address blogger Russell Brown said the comments appeared to be driven by a "troll pack" of users who were pushing the false rumour on the social media platform.

Dirty Politics author Nicky Hager said when contacted that there were people who used social media to leverage gossip and rumour to gain political advantage.

"They are trying to gain partisan advantage through damaging the Prime Minister by a campaign of innuendo."

Hager said the aim was to steer the public's political focus away from policy to personal issues which didn't even need to be true.

"They are trying to find personal or moral things — true or untrue — to smear and marginalise the political figures. It's never playing with a straight bat, never considering issues.

National Party leader Simon Bridges said he expected his MPs to be "above reproach" in their dealings with media.

"As leader I've repeatedly made my expectations very clear — National MPs will not be involved in peddling rumours or innuendo."

Political scientist Dr Bryce Edwards said it was not unusual for those in politics, or attached to politics, to be the subject of rumours, although the false Gayford rumours were "extraordinary [in] how far it has spread".

Edwards said it was a difficult issue for Ardern and Gayford to handle because the only real recourse was legal action - which would draw greater attention to the false rumours.

Defamation lawyer Steven Price said changes in culture driven by technology advances had led to a huge growth in people publishing material via the internet.

That had, in turn, led to an increase in defamation claims made by individuals against other individuals — a switch on traditional defamation which usually saw commercial publishers targeted in legal claims.

Price, who works as a barrister but is also a lecturer at Victoria University's Faculty of Law, said hosts of sites were not considered liable for comments unless he or she was aware of those comments.

The Harmful Digital Communications Act also provided a protection for site hosts by providing a "safe harbour" for those who had a complaints system through which objections to content could be lodged.