By A. Ananthalakshmi

KUALA LUMPUR (Reuters) - Malaysia searched on Monday for four Chinese tourists and a Malaysian missing after a boat on a Lunar New Year holiday cruise capsized off the coast of Borneo, tossing 30 people into stormy seas and killing three Chinese passengers.

The catamaran carrying 27 Chinese tourists and three crew members 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 in life jackets and swept away by the current, the head of the Malaysian Maritime Enforcement Agency (MMEA) said.

Adrift for several hours before help arrived, the tourists were picked up by fishermen, 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.

Provincial police chief Ramli Din said three people had been arrested for questioning, including the boat owner and captain.

Maritime officials said late on Monday 27 Chinese tourists were on the boat and not 28, as they had previously said.

Chinese President Xi Jinping had offered assistance and neighboring 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 maritime agency said.

Anxious relatives arrived and were 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.

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

China is one of Malaysia's main sources of tourists.

Ties between the two countries were strained in 2014 when Malaysia Airlines flight MH370 went missing on its way from Kuala Lumpur to Beijing. Most of its passengers were from China.

The search for the airliner ended this month with no clue of its whereabouts.

Malaysian Prime Minister Najib Razak called for a full investigation to determine why the boat sank.

"However, at the moment we must concentrate fully on the search and rescue efforts," he said in a statement.

China said it hoped Malaysia would conduct a fair and objective investigation and "ascertain the facts about the incident as quickly as possible," foreign ministry spokesman Geng Shuang said in a statement.

(Additional reporting by Alexandra Harney in Beijing; Writing by Praveen Menon; Editing by Clarence Fernandez)