Julian Assange, the whistleblowing figurehead behind the WikiLeaks scandal that exposed government secrets worldwide, has landed in Bangkok to refuel before he makes his way to the Northern Mariana Islands in the United States.

A charter flight flew Assange from London, and has reportedly touched down at Bangkok's Don Mueang airport at around 12:30pm.

A senior Thai official confirmed the news saying: "The plane is expected to refuel and resupply with water before departing at 9:00pm for Saipan island."

Assange has spent more than a decade either imprisoned or holed up in the Ecuadorean embassy in London to avoid extradition to Sweden on sexual assault charges which were later dropped.

The Australian editor is expected to plead guilty this week to violating US espionage law, after which he is due to be sentenced to 62 months of time served and return to Australia.

Assange was accused of publishing some 700,000 confidential documents related to US military and diplomatic activities in Iraq and Afghanistan, starting in 2010.

WikiLeaks announced that he had been granted bail, taken from Belmarsh jail to Stansted airport, northeast of London, and put on a plane.

The plea deal ends a lengthy tussle over US attempts to extradite Assange from Britain to face charges under the 1917 Espionage Act.

The deal was not entirely unexpected. US President Joe Biden had been under growing pressure to drop the long-running case against Assange.