Assange broke bail and sought refuge at the Ecuador's embassy in London in June 2012 to avoid extradition to Sweden for questioning under a European arrest warrant. He claimed that he would risk further extradition to the United States on espionage charges over his whistleblowing website if he went to Sweden.
The prosector in charge of the case has refused to interrogate the Australian national in London, arguing that it would be against Swedish legal practice and represent special treatment, a claim his lawyers now refute.
The lawyers accused the prosecutor of "passiveness" and demanded her replacement if she is not prepared to interview Assange in London.
"Assuming that the prosecutor does not have a prejudiced opinion regarding the question of guilt, and is prepared to treat the different versions objectively, it is obvious that an interrogation with Julian Assange would benefit everybody, including the injured parties," they wrote.