Two container vessels, one of them Singapore-registered, collided off a port in Malaysia's Johor Baru on Tuesday (Jan 3).

The Maritime and Port Authority of Singapore (MPA) said it was notified by the Johor Port Authority (JPA) of a collision between a Singapore-registered container vessel Wan Hai 301 and a Gibraltar-registered container vessel APL Denver off Pasir Gudang Port at 11.50pm on Tuesday.

One of the bunker tanks on the APL Denver was reportedly damaged and spilled approximately 300 tonnes of oil, MPA said in a press release on Wednesday.

JPA has deployed four anti-pollution craft and an oil boom to contain the oil spill.

Some oil patches were spotted in Singapore, with the spillage contained off the western of Pulau Ubin.

MPA said it has activated eight anti-pollution craft with dispersant spraying capabilities to clean up the oil.

There have been no reports of injury and traffic in the East Johor Straits and Singapore's port operations remain unaffected, MPA said.

As the tide is expected to move eastwards in the evening today, NParks has set up oil absorbent booms to protect the mangroves and mudflats along the north-eastern coasts of Pulau Ubin, including Chek Jawa Wetland.

"In addition, booms have also been set up to protect the mangroves at Coney Island Park and Pasir Ris Park," said an NParks spokesman.