WikiLeaks founder Julian Assange is not getting the time he needs with his legal team to discuss his fight against extradition to the United States, causing delays to the case, his lawyer has told a British court.

Key points: Assange's lawyer said difficulty in getting time with her client had delayed the case

Assange's lawyer said difficulty in getting time with her client had delayed the case Assange is being held in a British jail pending the US extradition case, having served a sentence for skipping bail

Assange is being held in a British jail pending the US extradition case, having served a sentence for skipping bail If extradited to the US, he will face 18 charges including conspiring to hack government computers and violating an espionage law

After skipping bail in the United Kingdom, Assange spent seven years holed up in Ecuador's embassy in London before he was dragged out by police in April last year.

He is being held in a British jail pending the US extradition case, having served a sentence for skipping bail.

The US wants him extradited to face 18 charges, including conspiring to hack government computers and violating an espionage law.

He could spend decades in prison if convicted.

The 48-year-old Australian appeared for the hearing at Westminster Magistrates Court wearing glasses and a dark blazer over a light top.

He spoke only to confirm his name and date of birth to the judge and saluted his supporters in the public gallery at the beginning and end of the hearing.

Assange says the US charges against him are a political attempt to silence journalists and publishers. ( AP: Kirsty Wigglesworth )

Assange's lawyer Gareth Peirce said the difficulty in getting time with Assange had delayed the case, telling the court: "This slippage in the timetable is extremely worrying".

He fled to Ecuador's embassy in 2012 to avoid being sent to Sweden to face sex crimes accusations that were dropped last year.

He says the US charges against him are a political attempt to silence journalists and publishers, and that the Swedish allegations were part of a plot to catch him.

Assange made global headlines in early 2010 when WikiLeaks published a classified US military video showing a 2007 attack by Apache helicopters in Baghdad that killed a dozen people, including two Reuters news staff.

Judge Vanessa Baraitser said Assange could have time to speak to his lawyer and appear in court again later in the day.

The WikiLeaks founder made global headlines in 2010 when he published a classified US military video. ( Alaska State Troopers via AP )

In that second sitting, Ms Peirce said that she had only had an hour to speak to Assange.

Full extradition proceedings are expected to commence in February.

Reuters