Two islands off the northeast corner of Johor were hit by oil spills but authorities were not certain of the extent of the damage, a report said today.

Johor tourism and environment official Freddie Long said the oil spill was near the islands of Pulau Besar and Pulau Tengah, the Star newspaper rpeorted.

Both islands are located off the coast of Mersing, which is the main port for ferries to the popular beach resort of Pulau Tioman and more than 40 other islands in the area.

"Department of Environment officers have been ordered to monitor the situation," the Star cited Long as saying. He said he was made aware of the spill at midday Friday.

A similar incident occured on Aug 6 in the town of Pontian in Johor where the state's seafood village of Kukup battled pollution when sludge flowed into open sea fish pens off the south western coast of Tanjung Piai,

Some 70 fish breeders with more than 7,500 cages were badly affected by the incident which was largely blamed on spillage from ships plying the Malacca Straits.