"The Philippines has been a leader in Internet freedom," said Harry S. Roque, president of Media Defense South East Asia, an advocacy organization. "This law makes the Philippines at par with other oppressive regimes in Southeast Asia that imprison and intimidate bloggers."
The new law, the Cybercrime Prevention Act of 2012, which was signed by President Benigno Aquino III on Sept. 12, sets penalties for a range of computer-related crimes including child pornography, identity theft, online fraud and illegal access to computer networks.
But critics are concerned about the law's provisions related to libel, which in the Philippines is a criminal offense that can result in imprisonment. Roque said the law applies the existing legal definition of libel to the online activities of individuals, meaning that if a comment on Facebook or Twitter were deemed libelous, the writer of the item and those who shared it could be prosecuted.
"It exposes Internet users to prosecution," said Roque, a law professor at the University of the Philippines. "You can be sued. You can be forced to post a bond. You will need to get a lawyer. You can imagine the mayhem this can cause."
There has been considerable public outcry against the law in the weeks leading up to its implementation. Hackers have attacked the websites of the president, both houses of Congress and a variety of government agencies. On Wednesday, some Internet users replaced their websites with blank pages to protest the law, while others took to the streets, staging a demonstration in front of the Supreme Court.
Some government offices have also struggled with the new law. "Foul words against our police officers can be used as evidence now to file a case against you in a court of law," a post by the Philippine National Police on their official Facebook page read Monday, in response to a negative comment by a visitor to the site. Police officials later apologized and removed the post.
Philippine senators who voted for the law, many of whom are up for re-election next year, have been scrambling to address critics' concerns. Some senators have had to admit they did not actually read the law before voting for its passage. Sen. Francis G. Escudero acknowledged on Tuesday on his website that he had not read the provision of the law dealing with online libel.
"In fact, I have a bill since 2007 that seeks to decriminalize libel," he said.
Sen. Edgardo J. Angara, who voted for the new law, said Wednesday -- the same day he filed his certificate of candidacy for re-election -- that he supported amending the legislation.
"Not all the laws that we pass are perfect," Angara told reporters. "At least in this case we are responsive."
A spokesman for Aquino sought Wednesday to calm public fears after the barrage of protests and an announcement by Justice Secretary Leila de Lima that her department would be hiring 150 investigators to enforce the new law.
"Our constitution is clear and uncompromising in the civil liberties it guarantees all our people," said the spokesman, Edwin Lacierda. "As the basic law, its guarantees cannot, and will not, be diminished or reduced by any law passed by Congress."
At least nine petitions have been filed with the Supreme Court seeking to halt the implementation of the law. The court has said it will rule on the matter next week.
In a study released before the law was passed, the organization Freedom House, based in the United States, ranked the Philippines sixth in the world in terms of Internet freedom.