"It has become incredibly hard and far more dangerous for every one of us," Ressa told reporters awaiting her arrival at Oslo's airport ahead of Friday's Nobel Peace Prize ceremony, where she will be honoured alongside Dmitry Muratov of Russia.

Ressa, the co-founder of the investigative news site Rappler, and Muratov, a co-founder of Russia's leading independent newspaper Novaya Gazeta, were given the award in October for their efforts to "safeguard freedom of expression".

Criticising "our authoritarian-style leaders and budding dictators" who "want us to voluntarily give up our rights", Ressa urged journalists to defend their rights.

"Now more than ever we need to protect our rights, otherwise we will lose them," she said.

"When facts are under threat, when you don't have integrity of facts, you cannot have integrity of elections. So it begins with us, we must keep getting the facts and serving the people," the former CNN correspondent said.

Ressa, 58, is a staunch critic of Philippine President Rodrigo Duterte and his government's policies, including a drug war that has killed thousands.

Her visit to Oslo was long uncertain. Currently on bail pending an appeal against a conviction last year in a cyber libel case, she applied to four courts for permission to travel to Norway for the ceremony.

Wearing a black facemask inscribed with the words "Journalism is not a crime", Ressa was emotional after her arrival and struggled to fight back tears in the icy temperatures.

"It's very cold but it's very warm."

The Philippines is currently ranked 138th in the world for press freedom on an annual list compiled by Reporters Without Borders, while Vladimir Putin's Russia is in 150th place.