A tanker that sank off the coast of the Philippines with 800,000 litres of oil on board did not have a proper permit to sail, according to officials.

Miles of coral reefs were affected by an oil spill when the 1,100-dwt Princess Empress (built 2022) sank last month after being hit by mechanical problems and heavy weather.

A senate hearing heard that the ship had sailed without a permit on nine occasions, including the fateful voyage, the Philippine Star reported.

Hernani Fabia, administrator of the Maritime Industry Authority, told the hearing that documents were missing for the pending application.

The listed owner, RDC Reield Marine Services, based in Manila, had a pending application “which we wanted to conduct a hearing on, but they were missing documents”, Fabia was quoted as saying by the Star.

“They were not issued a permit immediately,” he said.

The owner has insisted that the paperwork was in order, according to the Star.

The company has apologised for the spill and said it is doing everything possible to minimise the impact on the environment and clean up the spill.

The spill has affected 14,000 people working in the fishing industry and threatens more than 36,000 hectares of marine habitat, according to local reports.

Japanese coast guard officials have arrived to help with the clean-up, the head of the local coast guard, Artemio Abu, said on Monday. The US military has also offered to help.

Abu said the seaworthiness of the Princess Empress was “still under investigation”, according to a government statement.

The tanker has been located about 14km off the island of Mindoro and nearly 400 metres below the surface, he said.

Booms have been placed around the site and other efforts are being made to contain the spill.

The incident is likely to run up substantial claims, but the vessel does appear to be fully insured.

The owner’s protection and indemnity insurance is placed with the Shipowners’ Club, which is a member of the International Group of P&I Clubs.

The International Oil Pollution Compensation Funds has also been studying the case to evaluate if it is eligible to be included in the scheme.