Malaysia expanded a search on Monday for five Chinese tourists and a Malaysian missing after a boat capsized off the coast of Borneo, killing three Chinese passengers and tossing others into stormy seas.

The catamaran carrying 28 Chinese tourists and three crew sank late on Saturday as it sailed from Kota Kinabalu, the capital of the eastern Malaysian state of Sabah, to the tourist spot of Mengalum, Malaysian maritime officials said. 

The boat went down after being battered by heavy waves. The tourists were tied together and swept away by the current, the head of the Malaysian Maritime Enforcement Agency (MMEA) said.

Adrift for several hours, floating in their life jackets before help arrived, the tourists were picked up by the boats of fishermen who spotted them, Malaysian maritime officials said.

Three of the tourists were found dead on Sunday, while 22 people, including the boat's captain, were rescued.

Military ships and aircraft were scouring an area of 2,400 square nautical miles of sea, the agency said.

The search had been hampered by strong wind and choppy waters, officials added.

Chinese President Xi Jinping had offered assistance and neighbouring Brunei deployed a helicopter and naval assets to help.

The rescued passengers and crew arrived in Kota Kinabalu early on Monday and were taken to hospital, the agency said.

Anxious family members also arrived in the state capital on Monday, to be escorted to the hospital by Chinese embassy officials.

Authorities were investigating whether the boat should have been used as a tourist vessel, the MMEA's director-general, Ahmad Puzi Ab Kahar, told reporters.

"According to the skipper, the boat was 'broken' after being hit by strong waves, and sank. All the tourists were tied together and were carried away by the currents," he said late on Sunday.

Police have detained the captain and a crewman for questioning, media said.

Thousands of Chinese visitors flock to Mengalum island during the long Lunar New Year holidays.

Malaysian Prime Minister Najib Razak called for a full investigation to determine the cause of the tragedy.

"However, at the moment we must concentrate fully on the search and rescue efforts for six more victims who have not yet been found," he said in a statement.

China hopes Malaysia will conduct a fair and objective investigation and "ascertain the facts about the incident as quickly as possible," Chinese Foreign Ministry spokesman Geng Shuang said in a statement on its website on Monday.

Source: Timesofoman