Comments by British Foreign Secretary Jeremy Hunt that he would not block Julian Assange's extradition to the US proves the Australian has no chance of "fair and impartial treatment" by UK authorities, the editor of WikiLeaks says.

Jeremy Hunt said in a US TV interview on Sunday that what has happened to Assange in recent weeks - being dragged out of the Ecuadorian Embassy in London and jailed for a bail violation - was "the right thing".

Kristinn Hrafnsson, Editor-in-Chief of WikiLeaks, said: "In an interview timed for President (Donald) Trump's arrival to the UK, a grinning UK Foreign Secretary pledged WikiLeaks publisher Julian Assange's extradition to the United States will go ahead if he becomes the next prime minister.

"The Foreign Secretary incorrectly stated that the 'very serious crimes' for which Assange has been indicted are 'alleged to have led to people's deaths', even though there is no such allegation."

Hrafnsson said the latest comments follow Hunt's "insulting dismissal" of UN Special Rapporteur on Torture Professor Nils Melzer, who on Friday appealed to the UK Government not to extradite Assange to the US or to any other state because he would not receive a fair trial.

"Hunt's dismissal showed once again that Mr Assange has no chance of fair and impartial treatment at the hands of UK authorities."

The US is seeking to extradite Assange on spying charges, while Swedish prosecutors are to reopen an investigation into a rape allegation, which he has always denied.