Philippine President Benigno Aquino vowed Monday to acquire fighter jets, air defence radar and other equipment within three years to bolster the country's weak air force, amid a territorial dispute with China.

"I assure you that before I step down from office, our skies will be guarded by modern air assets," he said in a speech during a visit at an air base in Clark, north of Manila. The speech was broadcast live on radio and television.

Among these are "lead-in fighters, long-range patrol aircraft, close-air-support aircraft", as well as transport planes, attack- and multi-use helicopters, air defence radar and flight simulators.

He gave no details of the aircraft and equipment, or the terms for their acquisition.

In January an Aquino spokesman announced the government would buy 12 South Korean FA-50 fighter jets to be used for "training, interdiction and disaster response".

The Philippines, a former US colony, retired the last of its US-designed F-5 fighters in 2005 and lacks air defence.

Aquino, whose-six-year term ends in mid-2016, has set about modernising the military in his first three years in office as tensions rise with China over overlapping territorial claims to islands and waters in the South China Sea.

The main focus was initially the navy with the acquisition of two Hamilton-class cutters decommissioned by the US Coast Guard.

The first of the two refurbished vessels became the Philippine Navy's flagship in 2011, replacing a warship initially built for the US Navy in World War II.

The second cutter is set to arrive in the Philippines later this year.

Aquino said Monday he was committed to reversing the under-spending on military capability that he said had characterised the Philippines since the early 1990s.

"Over the past decades the air force had its wings broken and we relied on old and rickety planes and equipment," he said.

Parliament has since authorised the defence department to spend 75 billion pesos ($1.7 billion) on modernising the military over the next five years, Aquino added.

This is on top the more than 19 billion pesos that it had spent over the past three years for this purpose.

Between 1992 and 2010, the Philippines had spent just 33 billion pesos for military modernisation, Aquino said.