"In the context of the cyberworld, 'libel' is very difficult to determine since there are many actors in the cyberworld," including the blogger, the blog service provider, the Internet service provider, the person who comments on the blog and the person who posts a link to the blog site, he wrote.
Presidential spokesman Edwin Lacierda assured the public Wednesday that the constitution "is clear and uncompromising in the civil liberties it guarantees all our people."
President Benigno Aquino III's administration has not pursued any libel cases since he took office in 2010.
Lacierda criticized hackers who defaced many government websites in support of the movement against the cybercrime law, saying they engaged in online vandalism.
Many Facebook and Twitter users in the Philippines and the portals of the main media organizations have replaced their profile pictures with black screens as a protest against the law.