A leak occurred in a pipeline along the eastern seaboard of Thailand on Saturday and spilled 50- 70 tonnes of crude oil into the sea.

The pipeline, operated by PTT Global Chemical Plc (PTTGC), locates about 20 kilometers southeast of Map Ta Phut seaport in the eastern province of Rayong, the Bangkok Post reported.

Crude oil from an Omani tanker moored offshore was being transferred to the pipeline for delivery to a PTTGC refinery at Map Ta Phut, said the report.

Anon Sirisaengtaksin, chief executive of PTTGC, said the company immediately shut off the pipeline valve to prevent further spills and cooperated with the Royal Thai Navy and the Marine Department to contain the damage.

"All the crude had been eradicated an hour after the accident," he said.

He said the company would continue to monitor conditions in the Gulf of Thailand and make sure that tourists and fishermen who live nearby would not be affected.