WikiLeaks founder Julian Assange has lashed out at Swedish prosecutors who are dropping three sex assault claims against him, but still want to question him over a rape allegation.

The 44-year-old Australian said from his Ecuadorian embassy refuge in London on Thursday that the prosecutors had avoided hearing his side of the story entirely and their actions were “beyond incompetence”.

Swedish officials on Thursday confirmed that investigations into three allegations against him were being dropped as two had reached their five-year statute of limitations and a third would reach that point next Tuesday.

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But prosecutors say they still hope to question Assange on an allegation of rape that doesn’t expire until 2020.

Two women in Sweden made the 2010 sex claims, which he strongly denies.

Assange fought extradition to Sweden from the UK on fears he would be handed over to the United States over secret documents published by his whistleblowing organisation.

He has been granted political asylum by Ecuador and has been holed up at that country’s embassy for more than three years.

In a statement on Thursday, Assange said he was “extremely disappointed” as he was an innocent man who hadn’t been charged.

“From the beginning I offered simple solutions. Come to the embassy to take my statement or promise not to send me to the United States.

“This Swedish official refused both. She even refused a written statement,” he said, referring to Sweden’s Director of Public Prosecutions Marianne Nye.

“Now she has managed to avoid hearing my side of the story entirely. This is beyond incompetence. I am strong, but the cost to my family is unacceptable,” Assange said.

Media camped outside the Ecuador Embassy where Assange is hiding.  Photo: AAP

A statement on Thursday from Nye’s office said: “Julian Assange, on his own accord, has evaded prosecution by seeking refuge in the Embassy of Ecuador.

“As the statute of limitation has run (out) on some of the crimes, I am compelled to discontinue the investigation with respect to these crimes.

“I regret having to say that this means there will be no closure with regard to these events, as we have not been able to interview the suspect.”

The statement added that a Swedish request to interview Assange at the Ecuadorian embassy was submitted at the beginning of June, “but a permission has yet to be received”.

“I still hope, however, that I will be able to arrange for an interview, as there are ongoing negotiations between Sweden and Ecuador,” the DPP said.

Prominent Australian journalist John Pilger said that by dropping most of the allegations “Sweden has finally admitted to the grotesque injustice its judicial and political elite have perpetrated against Assange for almost five years”.

“Assange’s only crime is to have told the world about the epic lies, manipulation and warmongering of the United States,” he said in a statement.

“Those who have seen the ‘evidence’ in the Swedish case know it has been a farce from day one, including the allegation he is said to still face.”

Pilger slammed the Australian government’s “shocking abandonment of a citizen charged with nothing – for the craven purpose of appeasing a rapacious foreign power”.

Assange’s mother Christine described the behaviour of the Swedish prosecutor as “wicked, truly wicked” for knowingly perverting justice.

“I have privately shed many tears for many years – the terrible injustice of it all,” she told Britain’s Press Association.

“It has been five years of anguish seeing my son so cruelly politically persecuted and denied a proper legal process.”

– AAP