KUALA LUMPUR (Reuters) - More than 37,000 people have been affected by flooding caused by torrential rain in six Malaysian states this week, Prime Minister Anwar Ibrahim said on Thursday.

Anwar told parliament 322 temporary shelters had been opened in the states of Kelantan, Terengganu, Kedah, Perlis, Johor and Perak to house those displaced by floods.

The north-eastern state of Kelantan, bordering Thailand, has been the worst hit, with 30,582 people from 9,223 families affected, Anwar said.

Floods are common on the eastern coast of Malaysia during the annual monsoon season from October until March, with thousands of people displaced each year.

The Meteorological Department on Wednesday issued a red alert warning for continuous heavy rain - indicating dangerous levels of downpour - in Kelantan, Pahang and Terengganu states. It expects the rain to last until Friday.

The National Disaster Management Agency has been directed to mobilise all federal and state agencies to ensure the safety of flood victims and residents throughout the monsoon period, Anwar said.

(Reporting by Rozanna Latiff; Editing by Kate Mayberry)