The cost of policing the Ecuadorian embassy in London, where WikiLeaks founder Julian Assange is staying, has hit 2.9 million pounds ($4.3 million), Scotland Yard says.

Officers have been stationed there ever since Mr Assange was granted political asylum by Ecuador after he entered the embassy on June 19.

The Australian had lost his battle in the British courts against extradition to Sweden, where he faces questioning over allegations of sexual assault.

Ecuador says the UK government has failed to give assurances Mr Assange will not be extradited from Sweden to the United States.

On Saturday, Scotland Yard police headquarters estimated the total cost to the end of January to be 2.9 million pounds - 2.3 million pounds in salary for the officers stationed on duty and the rest in overtime payments.

The embassy is a flat in a mansion block in west London's plush Knightsbridge district.

Mr Assange, a 41-year-old former computer hacker, founded the WikiLeaks anti-secrecy website which enraged the US government by releasing US diplomatic cables, as well as war logs relating to the conflicts in Iraq and Afghanistan in the biggest security breach in American history.

A spokesman at the Ecuadoran embassy said: "The Ecuadoran government is concerned by the significant cost to the taxpayers of London of policing the embassy."

"However, we believe this expenditure could be avoided if the UK government would provide the undertakings that the Ecuadoran government has sought that there will be no onward extradition of Julian Assange to the United States.

"The Home Office (Britain's interior ministry) has the power to offer such an assurance but has so far declined to do so.

"Until we obtain these undertakings, the Ecuadoran government will continue to protect Julian Assange's human rights that are enshrined in international law."

Earlier this month, British heiress Jemima Khan became the latest defector from the WikiLeaks camp, declaring that Mr Assange risks becoming Australia's version of Scientology founder L Ron Hubbard.

The former wife of cricket superstar turned Pakistani politician Imran Khan, Ms Khan had been a high-profile supporter of Mr Assange and was one of the people who put up $30,000 to ensure his bail.

AFP/ABC