Severe floods caused by monsoon rains have killed more than 30 people and displaced tens of thousands in Malaysia and southern Thailand, with both countries preparing shelters and evacuation plans in anticipation of more heavy rain.

There are worries in Malaysia and neighbouring Thailand that disastrous flooding could get worse as more rain comes.

Malaysia and Thailand are facing a second wave of heavy rain and potential flooding this week, authorities said on Monday, even as some displaced residents were able to return home and the worst floods in decades began receding in some areas.