South Korea's coastguard said Monday it would take at least two weeks to clean up the shoreline fouled by an oil spill off the southwestern port of Yeosu.

More than 164,000 litres of crude oil spilt into the sea after a Singapore-registered tanker, Wu Yi San, hit a pier and pierced a pipeline on Friday.

A 10-kilometre (6.2 mile) stretch of coastline was affected by the incident.

"We're afraid of damage to fish farms in that area," Yeosu coastguard chief Kim Sang-Bae told reporters.

Hundreds of private, coastguard and naval vessels have been taking part in the clean-up, which Kim said would continue for another two weeks.

There was no leak of crude from the tanker itself.

South Korea's worst oil spill was in 2007 when 10,500 tonnes of crude poured out of a Hong Kong-registered supertanker after a collision with a Samsung Heavy Industries barge near the western port of Taean.

The spill devastated the region and triggered a number of suicides among local residents, as a legal wrangle over who was responsible and who qualified for compensation dragged on for years.