The outbreak of war in February sent pump prices soaring to record highs and forced President Ferdinand Marcos to declare a state of national energy emergency.

Energy Secretary Sharon Garin said a government-run national stockpile would aim to add at least 30 days' worth of stocks of petroleum products to the 30-60 day reserves that the government mandates for local oil companies.

A reserve would require a "huge investment", she said, with a single 500,000-barrel storage tank -- equivalent to the country's daily oil consumption -- likely costing five billion pesos ($81 million) to build.

The state-run Philippine National Oil Co. and the country's sovereign wealth fund Maharlika Investment Corp. were also being considered as funding sources, Garin said.

"This is to ensure that we do not run short of oil or go into panic each time a war breaks out in another country, that we are assured that for a certain number of days, we have a steady supply of oil," she told a news conference.

"We are happy to note that Japan will support this initiative by conducting necessary feasibility studies and providing capacity building in the development of a stockpiling system," she added.

She said Marcos secured the commitment during a state visit to Tokyo last month.