"We're still investigating the incident," said Danilo Abinoja, deputy chief coast guard, adding that there were no clear indications the oily sludge had spilled. The vessel's crew was rescued.

The barge was carrying debris from the site of the Solar 1, which sank in rough seas in August and leaked around 500,000 litres of bunker oil, affecting 40,000 people and more than 200 km (125 miles) of coastline in the central Philippines.

Around 1.4 million litres of oil remain trapped in the tanker, buried about 640 metres (2,100 feet) under water off central Guimaras Island, and authorities have said they will wait until calmer weather in January to siphon it off.

A spokesman for Petron, which had also chartered the Solar 1, said the company had sent equipment to clean up this latest sinking, adding that the debris "poses no threat to health".

Environment group Greenpeace said the oil group should be held accountable for the barge capsizing.

"Petron has yet to fully answer for its disastrous oil spill in Guimaras, but here it is again with another environmental disaster in the making," the organisation said in a statement.

Local officials said giant waves and strong winds could have caused the accident. Fishing had been prohibited in the area for four days ago due to bad weather.

"They (Petron) reported a thin layer of oil, like a rainbow on the water, not the thick sludge," Loreto Leo Ocampos, governor of Misamis Occidential province, told QTV television.

"They are assuring us that the (federal) government will look into it very quickly. They've alerted disaster agencies just in case there may be contamination."