KOTA KINABALU (THE STAR/ASIA NEWS NETWORK) - Four people are missing for more than a day after their boat left Sabah's northern Pulau Balambangan to Tanjung Simpang Mengayau in Kudat district.

The Malaysian Maritime Enforcement Agency and marine police have dispatched six vessels to search for the boat that carried two Spaniards, a Chinese national and a Malaysian.

An MMEA helicopter is expected to join the search on Wednesday (May 4).

MMEA Sabah and Labuan Region commander Maritime First Adminal Mohd Zubil Mat Som said the boat carrying four people is believed to be adrift after its engine failed.

He said there is no indication of the four being abducted.

Admiral Mohd Zubil said the missing have been identified as Spaniards David Hernades Gasulla and Martha Miguel, and Chinese national Tommy Lam Wai Yin.

The Malaysian on board the boat was identified only as Ms Ella.

Their boat left Pulau Balambangan at about 6pm on Monday and was due to arrive in Tanjung Simpang Mengayau two hours later.