MANILA:Philippine students and activists protested on Tuesday against a government decision to allow security forces to patrol the campuses of the country's biggest university after authorities accused it of being a breeding ground for communist rebels.

President Rodrigo Duterte's government has stepped up efforts to end a Maoist-led rebellion, one of the world's longest insurgencies that has killed more than 40,000 people.

But the United Nations had warned in a report that "red-tagging", or labelling people and groups as communists or terrorists, and incitement to violence have been rife in the Southeast Asian nation.

The government, in a decision made public late on Monday, scrapped a 1989 agreement that had prevented soldiers and police from entering the 17 campuses of the University of the Philippines (UP) without consent, except during emergencies or when in hot pursuit.

"This signals greater repression, harassment and harm among activists, youth and students and other people (who) they maliciously tag as communists, terrorists and will result in the militarisation of campuses," Eleanor de Guzman, secretary for human rights of a left-wing labour group, told a crowd of about 100 protesters.

Defence Secretary Delfin Lorenzana, justifying the decision to scrap the 1989 agreement, said in a statement the 112-year-old university "has become the breeding ground of intransigent individuals and groups whose extremist beliefs have inveigled students to join their ranks to fight against the government".

A number of UP students, some killed in military operations or captured, had been identified as members of the communist party's armed wing, the defence ministry said in a letter to the university's president, without providing evidence.

Academics and politicians also condemned the scrapping of the agreement saying it threatened academic freedom and opened the door to red tagging.

University President Danilo Concepcion urged the defence ministry to reconsider the decision while Vice President Maria Leonor Robredo, the opposition leader, said the action was "designed to silence criticism".

Since coming into power in 2016, Duterte's government has seen repeated breakdowns in peace talks with the communist rebels.