During the recent ruling that Assange should be extradited to Sweden to face questioning about allegations of sexual assault, District Judge Howard Riddle called Hurtig "unreliable" and accused him of deliberately misleading the court.

Judge Riddle also made claims that Hurtig, who was called to testify at the trial by Assange's British legal team, had deliberately given false information about the number of times Swedish prosecutors had tried to get in touch with him.

Swedish publication The Local reports that following the verdict, Hurtig said he rejected Judge Riddle's criticism.

"I'm a reliable person; I'm a reliable witness," he said.

However, the Swedish Bar Association has demanded that Hurtig provide an explanation for the behaviour mentioned by Judge Riddle.

"We sent Hurtig a letter last week and asked him to explain himself," Bar Association secretary general Anne Ramberg told the TT News Agency.

Ramberg said Judge Riddle's statements were an "extremely serious critique" of Hurtig.

"If I'm not satisfied with Hurtig's explanation, I may go to the Bar Association's governing board, and after that the disciplinary committee, which has the final say on any possible consequences," she said.

According to The Local, the most common complaints about Swedish lawyers come from outside the legal system, usually from clients, but it is not unusual for Ramberg to take the initiative herself and review a suspected case of professional misconduct.

Hurtig has until March 14 to provide a response to the Bar Association.