Lawyers for Edward Snowden have filed a lawsuit to seek guarantees that Norway will not extradite him to the US if he visits to receive an award.
Mr Snowden is a former National Security Agency analyst who leaked secret US surveillance details.
The US authorities have already asked Norway to extradite him to face espionage charges.
Mr Snowden, who lives in Russia, is to receive the Ossietsky freedom of speech award in November.
His lawyers said if he were extradited to the US, it would be “a foregone conclusion” that he would be convicted and jailed.
Mr Snowden is due to receive the Ossietzky Prize, for “outstanding efforts for freedom of expression”, in Oslo.
The Norwegian law firm Schjoedt filed the lawsuit to “get legally established that Norway has no right to extradite Snowden to the US”.
Hallvard Helle, the lawyer representing Mr Snowden, told Reuters: “US authorities have already asked that Snowden will be extradited to the US if he was to arrive in Norway.”
Mr Snowden left the US in 2013 after leaking to the media details of extensive internet and phone surveillance by US intelligence.
His information made global headlines when the Guardian newspaper reported that the NSA was collecting the telephone records of tens of millions of Americans.
Mr Snowden is believed to have downloaded 1.7 million secret documents before he left the US.
Although some consider him a traitor for his revelations, many others around the world say he is a champion of civil liberties.
In the US he faces charges that could put him in prison for up to 30 years.
He has been granted asylum in Russia.
Mr Snowden has said that he is willing to be extradited to the United States if the federal government guarantees he will get a fair trial.