Communist rebels in the Philippines have called off a truce with the government, almost two weeks ahead of schedule, raising concerns about the future of peace talks.

The Communist Party of the Philippines (CPP) blamed the government for their action on Wednesday, but a spokesman for President Benigno Aquino said the CPP just wanted an excuse to cut the ceasefire short.

A CPP statement said the truce, originally scheduled to run from December 20 to January 15, had ended at noon on Wednesday because it believed the government only wanted a truce to remain in place until then.

"The [communist New People's Army (NPA)] and the people's militias should immediately assume an offensive posture and confront and frustrate the enemy campaigns of suppression," the statement said.

However, Aquino's spokesman Edwin Lacierda said the government would observe the ceasefire until January 15.

He said the rebels had found an extended ceasefire to be "detrimental" to them so they chose to cut it short and blame the government.

"The CPP-NPA has always been making excuses... and now they're coming up with other stumbling blocks to peace," Lacierda told reporters.

Peace talks

The government and the CPP agreed to the ceasefire in mid-December when they held their first high-level peace talks for 13 months.

Southern Philippine military spokesman Lieutenant Colonel Lyndon Paniza said on Wednesday the CPP had already violated the ceasefire.

He said communist gunmen descended on the outskirts of the southern city of Davao on Monday and Tuesday, briefly holding two government militiamen and three civilians to intimidate them.

The CPP pulled out of peace talks in November 2011 after the government rejected rebel demands to free jailed comrades whom they claimed were consultants to the negotiations.

The Maoist rebels have been waging an armed rebellion to seize power since 1969 and more than 30,000 people have died in the conflict, according to the government.

The military estimates the current NPA strength at about 4,000 fighters, significantly down from more than 26,000 at its peak in the late 1980s.