Philippine journalist Maria Ressa, a prominent critic of President Rodrigo Duterte, was rearrested on Friday in what press freedom advocates called retaliation for her news site's dogged coverage of the government.

Ressa and her website Rappler have been hit with a string of criminal charges in recent months that have sent shockwaves through the Philippines' media scene, prompting allegations she and her team are being targeted for their work.

The latest charges allege she and colleagues at Rappler violated rules on foreign ownership of media. She was taken into custody after arriving at Manila's airport from a trip abroad.

"The press in this country is under attack... We won't take the threat sitting down," Ressa told reporters after her release on the equivalent of $1,700 bail.

"The rule of law has been weaponised."