STOCKHOLM (REUTERS) - Sweden and Ecuador have agreed to hold talks to break a deadlock over questioning Wikileaks founder Julian Assange, but investigations into three of four cases against him are likely to be dropped in the coming days due to statutes of limitation.

Assange, 44, has been holed up inside Ecuador's London embassy since June 2012 to avoid extradition to Sweden to answer allegations of sexual assault and rape.

The Australian, who denies any wrongdoing, fears Sweden may extradite him to the United States, where he could face trial over Wikileaks' publication of huge amounts of leaked government documents including classified US military and diplomatic documents in one of the largest leaks in the country's history.

Ecuador this week agreed to discuss a general bilateral accord with Sweden on legal assistance in criminal matters, thereby providing a potential opening for Swedish prosecutors to question Assange.

But it remains unclear when the talks will occur.

"Normally, these kinds of negotiations simply take time. This is nothing you do in a hurry," said Cecilia Riddselius, a senior Swedish justice ministry official.

Three cases of sexual molestation and unlawful coercion against Assange will almost certainly lapse because of a five year statute of limitation expiring on Thursday and next Tuesday.

A more serious charge of rape has five more years to run and is likely still to be investigated.

Claes Borgstrom, a lawyer representing the woman who filed the allegations against Assange that run out this month, said her client had "naturally wanted Julian Assange to answer in court".

Assange's lawyer, Thomas Olsson, said his client was also unhappy that legal procedures rather than the facts of the case would put an end to three of the charges against him.

Assange has criticised prosecutors for not trying to question him earlier at the Ecuadorian embassy, Olsson said, adding: "The investigation should have been concluded a lot sooner given the circumstances of the case."