The Communist Party of the Philippines made the move following President Rodrigo Duterte's decision to free its top leaders on Friday. They are set to fly to Oslo for negotiations aimed at ending one of Asia's longest insurgencies.
‘We hope that this ceasefire declaration will be reciprocated by the (government) as a show of all-out determination to move forward with peace negotiations,’ the party said in a statement.
The talks begin on Monday with both sides expressing optimism for reaching a political settlement after 30 years of failed negotiations.
The government estimates the 47-year-old rebellion has claimed 30,000 lives and impoverished vast swathes of the South East Asian nation.
Norway has acted as an intermediary in the talks. Duterte's predecessor Benigno Aquino had ended negotiations in 2013 after rejecting the communists' demand that he free all imprisoned guerrillas.
A spokesman for the president did not immediately respond to AFP on whether Philippine security forces would also observe a truce.
After winning a landslide election victory in May, Duterte declared a unilateral ceasefire last month, but ended it just five days later when a rebel ambush killed a government militia member and wounded four others.
‘To further bolster peace negotiations, the (party) and (its armed wing the New People's Army) are also open to discuss the possibility of a longer ceasefire,’ the rebel statement said.
However, this would only be possible after the government freed ‘all political prisoners’, it said, referring to 550 guerrillas detained by the government.
The rebel army is believed to have fewer than 4,000 gunmen left, down from a peak of 26,000 in the 1980s, when a bloodless ‘People Power’ revolt ended the 20-year dictatorship of the late president Ferdinand Marcos.
But the movement retains support among the poor in rural areas, and its forces regularly kill police or troops while extorting money from local businesses.
Hours after the release of guerrilla chief Benito Tiamzon and his wife in Manila on Friday, police said they had arrested another senior rebel leader, Amelia Pond, in the central city of Cebu.
The woman is to stand trial for two murders as well as attempted murder, a police statement said.