Floods have killed at least two people and forced more than 50,000 to flee their homes as torrential rains in four states engulfed whole towns and villages.

The bodies of two men have been found in Segamat district Johor, the area worst hit by heavy monsoon rains, said Che Moin Umar, head of disaster management at the Civil Defense Department.

A third body in Johor's Kota Tinggi district was still being identified and a cause of death being determined, he said.

"Two people have died already due to the floods ... The younger man's body was discovered yesterday, while the body of the second victim, a 70-year-old man, was found today in Segamat," Che Moin told AFP .

He said the elderly man could not escape the flood waters that rushed through his village because an earlier stroke had left him partially paralysed.

"The currents are very strong this year, and in Johor it is (so) tremendous, that even the rescuers on boats are having difficulty in navigating the current."

Relief efforts were underway today in Johor and the neighbouring states of Negeri Sembilan, Malacca and Pahang, which have been affected by heavy north-east monsoon rains.

Health authorities said they had stepped up vigilance to prevent outbreaks of waterborne diseases in relief centres across the affected states, where thousands of evacuees are camped out.

Disease control

The Health Ministry's director of disease control, Ramlee Rahmat, said possible disease outbreaks during floods include cholera and dysentery, as well as respiratory illnesses.

"We have dispatched our health teams to oversee the sanitation especially at the evacuation centres," said Ramlee.

"Definitely we are most concerned of the possibility of the spread of cholera and especially in food preparation, we are monitoring the standards of hygiene," he said.

Officials said 45,448 people had been evacuated from Johor, 5,573 people from the popular tourist state of Malacca, 500 people in Negeri Sembilan, and 309 in Pahang.

The floods have also triggered mudslides, forcing road closures and the suspension of east and south-bound rail services, including to Singapore.

Newspaper pictures showed the town of Segamat in Johor completely inundated, with only rooftops protruding from the brown waters, and cars floating down streets.

Parts of Johor yesterday recorded rainfall of up to 66.3 centimetres, with an average of 40 centimetres throughout the state. A daily reading above 20 centimetres is deemed high.

The Meteorological Department said rains are expected to continue until the weekend.