Malaysia on Sunday pledged more funds to help over 160,000 people hit by the country's worst flooding in decades, as forecasters warned fresh rain could hamper efforts to relieve thousands left stranded by the waters.

Prime Minister Najib Razak announced an additional 500 million ringgit ($143 million) after touring parts of Kelantan state Saturday, which along with northeastern Terengganu and Pahang regions has been worst hit by the deluge.

Eight people have reportedly been killed so far by the torrential monsoon rains, and fears are mounting that the toll could rise as communities have been left stranded without food or medicine.

"The country is in desperate need of more helicopters," deputy transport minister Aziz Kaprawi said on Sunday, as rescue agencies warned that shortages of fuel and clean water were hampering search efforts.

The worst flooding in 30 years has devastated much of northern Malaysia, with some 8,000 people thought to have been left stranded across the impoverished Kelantan state, where 17 areas have been cut off by the rising waters.

From the air, state capital Kota Bharu appeared like a vast, muddy lake and left largely without power. Locals said many people had turned to looting because of a lack of fresh food and water supplies.

Weather forecasters on Sunday warned that much of Malaysia will see more storms in the next three days.

"We expect another surge in heavy rain followed by strong winds brought by the seasonal northeast monsoon, which usually continues till March," a meteorological department official told AFP.

"It is going to take time for the flood waters to subside."

- 'Not enough' -

Anger has been mounting across Malaysia at what is seen as the government's slow response to the crisis.

Truck drivers are complaining of diesel shortages as many petrol stations have been submerged while at relief centres, workers are struggling to cope without enough clean water and in the face of unsanitary conditions.

Prime Minister Najib has faced a storm of criticism after being pictured playing golf with US President Barack Obama during the storms.

The premier on Sunday defended his "golf diplomacy", with the Sunday Star newspaper quoting him as saying "it is hard for me to turn... down" a personal invitation by the US head of state.

The government has since stepped up its response to the crisis, pledging the extra 500 million ringgit to help cope with the crisis on top of 50 million ringgit already allocated.

But victims of the flooding said that still wouldn't be enough.

"I don't think Najib's 500 million ringgit money is enough. There are just too many victims," 58-year-old Tuan Sri Kuning told AFP.

"The conditions in the relief centre are very dirty with rubbish not collected, and it is infested with mosquitoes. We have limited drinking water."

Some people have started flying their sick parents out of the state themselves.

"Our home is totally submerged," said Ahmad Wajih Saifullah, a 25-year-old engineer who returned to Kelantan to evacuate his elderly and sick parents back to the Malaysian capital Kuala Lumpur.

"My mother has high blood pressure and diabetes. She lost all medicine when they had to abandon their homes quickly due to fast rising waters.

"I went to pharmacy shops and hospitals but was told that there were no one to disburse the medicine."