Former Prime Minister Sir John Key says it is outrageous Facebook is refusing to pull posts that link to an entirely fake NZ Herald website in which Key is purported to endorse Bitcoin.

Key is featured prominently in the fake Herald web page - set up by an overseas website - which includes claims he had told Bloomberg he had invested in Bitcoin early on and an initial $1000 investment was now worth $300 million, all of which Key said was false.

The Herald is also fighting to have the website taken down.

Key, a former currency trader, said he had never invested in Bitcoin.

Key, who is the chair of ANZ Bank, said since the web page started circulating he had been contacted by people thanking him for the advice and saying they had invested on the basis of it.

He had contacted Netsafe to try to get the web page removed and to get Facebook to remove posts which linked to it, but Facebook had declined to do so.

"This is outrageous. People are at risk here and you'd think Facebook would take their responsibilities seriously."

Facebook has been contacted by the Herald for comment.

The website has also been circulated on Twitter via the @setzerralf1 account and while some other users appeared to take it seriously many questioned whether it was "fake news".