Julian Assange, who is wanted by the authorities in Sweden for questioning over rape allegations, has spent the last three years held up in the Ecuadorian Embassy in London where he was granted asylum.
Thomas Olsson, one of Assange's team of lawyers released a statement:
"We consider that there have arisen a number of new circumstances which mean there is reason to review the earlier decision."
Assange has always denied the accusations of rape and claims the case is part of a wider conspiracy to see him extradited to the United States, where he could be charged with espionage for leaking classified documents.
The formal request by Assange's lawyers in Sweden follows the recent ruling by a United Nations Working Group that the WikiLeaks founder had been arbitrarily detained.
The Working Group on Arbitrary Detention ruled that Mr Assange's detention was contrary to various provisions of the International Covenant on Civil and Political Rights and called upon the UK and Sweden to ensure his safety and physical integrity, to facilitate the exercise of his right to freedom of movement, and to pay him compensation.
More recently, Dinah PoKempner, general counsel of Human Rights Watch, called on the British and Swedish governments to take heed of the groups' ruling.
The Office of the UN High Commissioner for Human Rights says the opinions of the Working Group should be taken into consideration by the UK and Sweden as they are based on international human rights law that binds the relevant states.
"Their failure to give due consideration to these international rights and obligations is what drove the conclusion that Assange's confinement is 'arbitrary.' "
Julian Assange filed a complaint in 2014 with the UN Working Group, arguing that he was "arbitrarily detained" because he could not leave the Ecuadorian embassy without fear of being arrested and extradited to Sweden — and subsequently — the US.