Manila - Hundreds of political activists and even petty criminals are being tortured in the Philippines, the head of the country's independent human rights body said, urging lawmakers to ratify a U.N. protocol to prevent it.

"Torture is prevalent," Leila de Lima told a news conference in Manila on Tuesday. "It's almost a daily occurrence in our ordinary precincts or police stations."

De Lima, named head of the rights body early this year, said her office has documented more than 300 torture cases since 2005, but there could be more cases not brought to her attention.

She said even ordinary civilians who got arrested or were detained arbitrarily by army or police forces were likely to be beaten up or harmed through electric shocks, cigarette burns or suffocated by plastic bags.

The rights body said it believed one effective strategy to end the physical abuse of prisoners and detainees was to allow unannounced visits to detention facilities anywhere in the country.

Last week, soldiers stopped seven lawmakers and a team from the rights commission from visiting detained marine officers facing charges for plotting against the government in 2006.

De Lima said she sent a letter to military chief, General Alexander Yano, this week, demanding access to army detention centres as part of the rights body's constitutional mandate.

The Philippines is likely to ratify the U.N. protocol on prevention of torture this year.

Eduardo Ermita, the executive secretary of President Gloria Macapagal Arroyo, said Manila wanted to delay the actual enforcement of the protocol by three to five years in order to improve the country's jail facilities.

He said the interior and local government department was building newer and bigger prison facilities, raising them to U.N. standards as well as trying to decongest jails.