A Swedish lower court has upheld the arrest warrant for Julian Assange, saying the Wikileaks founder's stay at Ecuador's London embassy did not equal detention.

Assange, 44, is wanted by Swedish authorities for questioning over allegations, which he denies, that he committed rape in 2010.

An Australian computer hacker who enraged US authorities by publishing hundreds of thousands of secret US diplomatic cables, he has been holed-up in the embassy since June 2012 to avoid the rape investigation in Sweden.

He says he fears further extradition to the United States, where there has been a criminal investigation into the activities of Wikileaks.

"The district court finds that there is still probable cause for the suspicion against JA (Julian Assange) for rape, less serious incident, and that there is still a risk that he will depart or in some other way evade prosecution or penalty," the court said in a statement.

Last year, Sweden's Supreme Court rejected a previous appeal by Assange to revoke a detention order.

Following a statement by a UN panel that his stay in the embassy amounts to arbitrary detention, Assange's lawyers again in February asked the Stockholm District Court to overturn the warrant for his arrest.

"Unlike the UN Working Group on Arbitrary Detention the district court does not consider JA's stay at the Embassy of Ecuador in London a form of detention," the court said.

Assange will appeal the ruling, said Per Samuelsson, one of his Swedish lawyers.

"I just spoke to him, and like us he is not surprised but very critical and angry," he said.

"The Swedish justice system only takes into consideration the Swedish bit, and not the whole situation given the tough sentence hanging over him in the United States."

In 2010, Wikileaks released more than 90,000 secret documents on the US-led military campaign in Afghanistan, followed by almost 400,000 US military reports detailing operations in Iraq.

Those disclosures were followed by release of millions of diplomatic cables dating back to 1973.

Reuters/AFP