Coconut meat trader Federico Bico, 56, a son and two bodyguards were killed after engaging seven New People's Army (NPA) gunmen who arrived on their farm demanding money, local military spokesman Major Harold Cabunoc said.

The bloody incident happened on Friday night near the town of Libmanan, 250 kilometres (155 miles) southeast of Manila.

"Bico owns a big coconut meat business. Last year the NPA demanded 30,000 pesos (about 685 dollars) in revolutionary taxes but he refused and hired bodyguards," Cabunoc told reporters by telephone.

Government forces summoned to the farm discovered the bodies of two of the suspected attackers nearby, both with fatal gunshot wounds, he added. Coconut meat is a key Filipino farm export used to manufacture vegetable oil.

The attack occurred ahead of formal peace talks scheduled in Norway on February 15.

The 4,700-member NPA has been waging a Maoist rebellion in the Philippine countryside since 1969 that the military said is financed mainly through extortion of local businesses and politicians.

The Oslo negotiations would be the first formal talks between the two sides since negotiations broke down in 2004.