A resident walks past a "Storm Warning" poster in Manila after Typhoon Sarika slammed central and northern Reuters

The Vietnam government said on Sunday that at least 21 people died and eight are still missing in four central provinces in the past week due to massive floods, as the country braces for Typhoon Sarika.

The government said the typhoon is expected to hit the Quang Binh province by Wednesday. Fifteen of the victims were from this province.

Typhoon Sarika was moving towards the South China Sea before it barreled into northern Philippine provinces on Sunday. The local weather bureau said they are monitoring the typhoon closely and that it could cross the eastern boundary by Monday.

The Deputy Prime Minister of Vietnam Trinh Dinh Dung urged the authorities on Sunday to reinforce key infrastructure projects in 22 coastal provinces and to decide evacuation plans.

He assured that the government would provide food relief in flooded areas.

According to a Vietnam Television (VTV) broadcast, he said: "We need to focus on searching for the missing".

The state-run VTV warned its viewers that many reservoirs were nearly full and could burst at any time. It also showed footage of people stranded on the roofs of their houses.

A government report showed that around 500,000 people have been already displaced and more than 100,000 houses were submerged and damaged by floods.

The disaster officials in the Philippines said the typhoon unleashed heavy rainfall and strong winds on northern rice-growing regions but there were no confirmed casualty reports.

They added that initially the total damage to farm crops, mostly rice and corn, was estimated at 53.5 million pesos (S$1.5 million).

According to the weather forecasters, as typhoon Sarika was moving out of the country it packed winds of up to 120kmh on Sunday afternoon.

The authorities said almost 2,552 families, or 12,496 individuals had been pre-emotively evacuated before the storm caused landfall early on Sunday. 160 domestic and international flights and a number of ferry services were cancelled due to Sarika.

The weather bureau has reduced the level of storm warning signals, but it said the authorities are keeping a close watch on Haima, which is apparently the next weather disturbance.

"It's still far, out of the Philippine Area of Responsibility, but it's now on the level of a storm. Over time, while travelling over water, it gains strength, so that's our next concern," Ricardo Jalad, the executive director of the National Disaster Risk Reduction and Management Council told The Straits Times.

Jalad said Typhoon Sarika did not cause "that serious" damage compared with what had been initially expected. However, he said there were several reports of landslides and flooding in some areas.

Referring to the town where typhoon Sarika caused landfall, he said: "We were focused on Baler, but local officials were able to conduct pre-emptive evacuation, so there was no casualty."