By Sarah Toms
BBC News, Manila
Heavy rains and strong winds have been hampering efforts to clean up the worst oil spill to hit the Philippines.
The oil spill has been spreading throughout fishing grounds
The Philippines has said it plans to ask Japan and Indonesia to help contain the huge spill around Guimaras island.
The spill has polluted fishing grounds, dive spots and a national marine reserve in the central Philippines.
Some two million litres of oil were on board a tanker that sank on Friday, and could damage the country's vital tourism industry if the slick spreads.
The coastguard is asking local governments to use wood and tyres to create a floating barrier to help contain the slick to stop it spreading to other coastal areas.
Oil is seeping from the tanker, which sank during a violent storm on Friday.
The Philippines lacks equipment to stop the spread of the oil and salvage the submerged tanker, prompting officials to say they will ask Indonesia and Japan for help.
The tanker was on its way to deliver two million litres (530,000 gallons) of oil to a power plant on the southern island of Mindanao.
Eighteen crew were rescued but two are still missing.
Many parts of the Philippines are renowned for white beaches and transparent waters, attracting tourists who bring in much-needed cash.
But now coastguard officials say the oil is wreaking havoc on the fishing grounds, diving spots and marine sanctuaries surrounding the central island of Guimaras.
One of the affected areas is the Taklong Island National Marine Reserve, a feeding and breeding ground for fish and other species.
It is believed the spilled oil could take up to three years to clean up.