PHILIPPINES has passed a landmark law that criminalizes "enforced disappearances", a presidential spokesman said on Saturday, in a move hailed by human rights groups.

Under the new law, enforced disappearances—or abductions carried out by government forces—will not be treated as cases of ordinary kidnapping and could invite up to life imprisonment as punishment.

It also prohibits secret detention facilities and authorizes the government to conduct "regular, unannounced . . . inspections of all places of detention and confinement".

President Benigno Aquino 3rd approved the legislation on Friday, the spokesman said, amid a growing outcry over alleged abductions of activists and government critics by security forces as part of their campaign against communist rebels.

Human Rights Watch welcomed the move, saying that "this law is a testament to the thousands of 'disappearance' victims since the Marcos dictatorship, whose long-suffering families are still searching for justice".

"The challenge now is for the government to move quickly to enforce the new law," HRW said in a statement.

"Disappearances" of activists rose sharply after then-president Ferdinand Marcos declared martial law in 1972. Although Marcos was toppled in a popular revolt in 1986, activist groups say the abductions still continue.

Communist guerrillas have been waging an armed rebellion in the Philippines since 1969 and over 30,000 people have died in the conflict, according to the government.

The military estimates the current strength of the guerrillas at about 4,000 fighters, significantly down from over 26,000 at its peak in the late 1980s.