Thailand's navy and pollution experts worked together on Thursday to clean up an oil spill near one of the country's most beautiful beaches after an undersea pipeline leaked up to 50 tonnes of crude.

The Pollution Control Department of the Kingdom of Thailand has warned that the spill in the Gulf of Thailand, approximately 20 kilometers (12 miles) off the coast of Rayong Province, could endanger a national park on nearby Ko Samet Island.

Weak currents have kept the oil away from coastal areas, and no impact on marine life or seafood farming has been reported so far, according to officials.

The spill volume was between 20 and 50 tonnes, or 22,000 to 60,000 liters, according to Star Petroleum Refining Public Company Limited, which operates the pipeline.

Divers discovered a failure in a flexible hose that was part of the undersea equipment surrounding a single point mooring – a floating buoy used to offload oil from tankers, according to the company.

Officials said at a joint news conference with the navy and other agencies that the Pollution Control Department and other experts are determining what type of dispersants to use on the spill.

A pipeline leak in the same area in 2013 caused a major slick that coated a beach on Ko Samet, necessitating the use of protective suits by recovery workers to clear the blackened sand.