Despite its champions being honoured with a Nobel Peace Prize, press freedom has a "sword of Damocles" hanging over it, this year's two laureates lamented on Thursday.

Maria Ressa of the Philippines, co-founder of the news website Rappler, and Dmitry Muratov of Russia, editor of the independent newspaper Novaya Gazeta, will receive their prize in Oslo on Friday for "their efforts to safeguard freedom of expression."

"So far, press freedom is under threat," Ressa told a press briefing, when asked whether the prestigious award had improved the situation in her country, which ranks 138th in the Reporters Without Borders (RSF) press freedom index.

The 58-year-old journalist mentioned her compatriot and former colleague, Jess Malabanan, a reporter for the Manila Standard, who was shot in the head on Wednesday.

Malabanan, who was also a Reuters correspondent, had worked on the sensitive subject of the war on drugs in the Philippines.

"It's like having a Damocles sword hang over your head," Ressa said.

"Now in the Philippines, the laws are there but... you tell the toughest stories at your own risk," she added.

Nobel Peace Prize winner Maria Ressa takes a selfie with fellow winner Dmitry Muratov as both warn of ongoing threats to press freedom
Nobel Peace Prize winner Maria Ressa takes a selfie with fellow winner Dmitry Muratov as both warn of ongoing threats to press freedom NTB via AFP / Torstein Bøe

Ressa, whose website is highly critical of Philippines President Rodrigo Duterte, is herself the subject of a total of seven lawsuits in her country.

Currently on parole pending an appeal after being convicted of defamation last year, she needed to ask four courts for permission to be able to travel and collect her Nobel in person.

Sitting beside her on Thursday, Muratov, 60, concurred with his fellow recipient's words.

"If we're going to be foreign agents because of the Nobel Peace Prize, we will not get upset, no," he told reporters when asked of the risk of being labelled as such by the Kremlin.

"But actually... I don't think we will get this label. We have some other risks though," Muratov added.

The "foreign agent" label is meant to apply to people or groups that receive funding from abroad and are involved in any kind of "political activity".

"Foreign agent" organisations must disclose sources of funding and label publications with the tag or face fines.

Novaya Gazeta is a rare independent newspaper in a Russian media landscape that is largely under state control. It is known for its investigations into corruption and human rights abuses in Chechnya.