A Swedish court on June 3 rejected a request to detain Australian whistleblower Julian Assange over a 2010 rape case, complicating the prosecutor's efforts to request his transfer from Britain.

The court said it shared the prosecutor's opinion that the Wikileaks founder was suspected of rape and "that there is a risk that Julian Assange will fail to appear or in some other way avoid participation in the investigation".     

But it ruled in favour of Assange's lawyer and said a detention order was not "proportionate," given that he is imprisoned in Britain and the prosecution could therefore proceed with the investigation in other ways.    

Swedish deputy director of public prosecutions Eva-Marie Persson had told the court that Assange had not cooperated with the Swedish investigation previously, fleeing from an extradition order, and therefore needed to be detained and questioned in Sweden.  

She asked the court to order Assange's detention in his absence, a standard part of Swedish legal procedure if a suspect is outside the country or cannot be located.    

It would have been the first step towards issuing a European Arrest Warrant to request Britain to extradite Assange to Sweden.    

"The purpose of this detention is to be able to complete the investigation and bring Julian Assange to justice," Persson said.    

Assange's Swedish lawyer, Per E Samuelson, meanwhile argued that a detention order was "meaningless" as Assange was not currently a flight risk.    

He said it was not proportionate to ask for someone's detention merely to conduct a questioning session.