Philippine government agents have again arrested the top executive of a news website that President Rodrigo Duterte has targeted for its critical coverage of his bloody drug war.

Maria Ressa, chief executive of online news platform Rappler, was served with an arrest warrant at Manila's international airport early yesterday, after she returned from a business trip in San Francisco.

She was released at around noon, after posting bail.

Her arrest stemmed from new charges filed this week accusing her and Rappler's board members of violating the country's anti-dummy law which bars Filipinos from acting as owners of local firms on behalf of foreigners. It imposes limits on foreign ownership of Philippine companies. In most cases, foreigners can have, at most, a 40 per cent stake in local firms and properties. Media companies like Rappler, however, should be 100 per cent Filipino-owned.

Prosecutors claimed that Ressa and six of Rappler's board members broke the anti-dummy law in 2015 when they granted Omidyar Network, a fund created by eBay founder Pierre Omidyar, the means to exercise control over the site, or veto powers on company decisions.

Although Omidyar transferred its stake to Ressa and Rappler's board members last year, that made them "dummies" for Omidyar, according to prosecutors.

"This is a travesty of justice. I have done nothing wrong. I am not a criminal. I am treated like a criminal," Ressa said in a tweet, as she was being led to a court where she posted bail. Before leaving San Francisco for Manila, she had tweeted: "Coming home to confront yet another ridiculous criminal case."

Mr Duterte's spokesman Salvador Panelo insisted at a news conference that Ressa's arrest followed due process. "When Maria was charged, there was a preliminary investigation on that. Then probable cause was determined. Due process has been observed," he said.

Last year, the Philippines' Securities and Exchange Commission (SEC) ruled that Rappler violated laws barring foreign ownership and control of local media, and moved to revoke its registration. An appellate court later ruled that while Omidyar's stake represented "some foreign control", the SEC should have let Rappler correct the error instead of shuttering it, which it said should be a "last resort". The court upheld that ruling on March 11.

Rappler insisted Omidyar was never given voting rights, and so never had a say in its operations.