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.

At least 13 people died and tens of thousands evacuated in one of the worst floods in decades to batter southern Thailand and northern Malaysia.

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

Floods in northern Malaysia and southern Thailand have claimed the lives of at least 12 people, and 135,000 individuals have been forced to leave their homes. Authorities warn that the number of casualties may increase.

Severe flooding caused by days of torrential rain has forced over 122,000 people to evacuate their homes across Malaysia, with disaster officials confirming three fatalities. Authorities warn that the numbers could rise as heavy rain and storm warnings persist.