KOTA KINABALU (THE STAR/ASIA NEWS NETWORK) - Search and rescue personnel have picked up two life jackets in the sea not far from where most of the 20 survivors of the catamaran tragedy were rescued five days ago.

The life jackets were discovered in waters near the Semarang offshore oil platform by crew of the Malaysian Maritime Enforcement Agency (MMEA) patrol vessel KM Berani on Friday (Feb 3).

MMEA officials could not immediately ascertain if the orange-coloured life jackets were those used in the ill-fated vessel as the name of the tour company that owned the catamaran was not printed on it.

The life jackets were being handed over to the police for verification.

KM Berani commanding officer Lt Kmdr Mohd Fauzi Ab Rahman said that the first life jacket was spotted at about noon on Wednesday while his crew recovered the second one at about 10am on Thursday.

He said the life jackets were found within the same vicinity and was about 30 nautical miles where the catamaran tragedy survivors were rescued.

"The location was about 84 nautical miles from Kota Kinabalu and about 32 nautical miles from Pulau Mengalum," he said at the MMEA office.

KM Berani had returned to Kota Kinabalu at about midnight on Friday for replenishment of supplies and to hand over the floating debris it had found in the search area, including a white buoy.

He said the calm sea in the morning and early afternoon made it possible for the crew to spot floating objects.

He said the seas in their search area would turn rough in the late afternoon, hampering search efforts.

MMEA Director for Kota Kinabalu Laksamana Pertama Adam Aziz said the search area for the remaining five China nationals and the Malaysian crewman of the catamaran had been reduced to 2,990 sq nautical miles.

He said 21 vessels and aircraft were involved in the search in waters in the south-west of Sabah, Brunei and northern Sarawak.

On Jan 28, the catamaran with 31 people on board - comprising 28 Chinese nationals and three crew members - sank at about 10am after departing from the Tanjung Aru jetty an hour earlier.

Twenty of the Chinese nationals survived their 30-hour ordeal at sea and two crewmen were also rescued. Three people died while six are still missing.

The missing six are crewman Absoy Kasim, 26, and China's Sheng Jiang Jiang, 50 (male), Luo Hong Yuan, 51 (male), Dong Mei (female), a woman in her 30s and a child believed to be aged 10.