The Philippines will buy 12 South Korean FA-50 fighter jets to strengthen its poorly-armed military, government spokesmen said Wednesday, amid increasing maritime tensions with China.

The FA-50s will be the first fighter jets to be operated by the Philippine air force since it retired the last of its US-designed F-5 fighters in 2005, said President Benigno Aquino's spokesman Edwin Lacierda.

"We don't have any existing jets right now that are in use, therefore it is necessary for us to upgrade. This is part of the ongoing process of modernising our military hardware," he told reporters.

Lacierda said the jets would be used for "training, interdiction and disaster response" and would use their aerial cameras to survey areas.

He stressed that the planned purchase was "not aimed at any particular country" despite the new tensions with China over conflicting maritime territorial claims in the South China Sea.

Defence department spokesman Peter Galvez said the FA-50 was chosen because it fitted all the country's requirements and because of its cost, adding that 18.9 billion pesos ($309 million) had been budgeted for their acquisition.

Manila will now begin negotiations for the aircraft, he said, adding that the government will seek to have two planes delivered as soon as possible so Filipino pilots can begin training on them.

In recent months the cash-strapped Philippines has stepped up efforts to modernise its military in the face of increasing Chinese assertiveness in pressing its claims to most of the South China Sea.

Although the Philippines has long relied on its defence ties with the United States for most of its arms, it has recently been seeking more weaponry from other countries like Poland, Spain, Italy, Canada and France.

President Aquino discussed acquiring more South Korean military equipment when South Korean President Lee Myung-Bak visited the country in November 2011.