Millions of people in the Philippines endured a second sweltering day without power on Thursday after a ferocious typhoon paralysed the capital and tore down flimsy rural homes, claiming at least 38 lives.

Authorities expressed frustration as reports from badly damaged areas filtered in and the death toll from Typhoon Rammasun, the first major storm of the Southeast Asian archipelago's rainy season, was nearly doubled to 38.

"We still have to find out what exactly are the reasons a lot of our countrymen refuse to heed the warnings," National Disaster Risk Reduction and Management Council chief Alexander Pama told reporters.

As part of a "zero casualty" effort, the government evacuated nearly 400,000 people from the path of Rammasun and warned others to stay indoors.

But many of the people who died were outdoors, killed by falling trees, collapsing buildings and flying debris, according to the council's data.

Pama said the death toll could rise further, with mobile phone and other forms of communication still cut to some rural areas. He said at least eight people remained missing.

Rammasun, a Thai word for "Thunder God", swept in off the Pacific Ocean on Tuesday night, then brought wind gusts of up to 160 kilometres an hour (100 miles) across land to Manila and other heavily populated northern regions.

"It really scrambled whole towns, blowing down houses and toppling power lines," the chairman of the Philippine Red Cross, Richard Gordon, told AFP.

The typhoon cut electricity supplies to nearly all of Manila, a megacity of more than 12 million people, and surrounding urban areas.

Schools and government offices were closed throughout the capital, hundreds of flights suspended and the stock exchange closed.

The stock exchange and government offices re-opened on Thursday, but many schools remained closed partly because of the power problems.

- Misery without power -

The Manila Electric Company (Meralco), the country's largest power distributor which serves the capital and surrounding areas, said 1.9 million households still did not have power on Thursday.

With the temperature in Manila expected to hit 30 degrees Celsius (85 degrees Fahrenheit) and the air thick with tropical moisture, Meralco could not give any estimate to frustrated residents when power would be restored.

Pama also said that electricity still had not been restored in the eastern region of Bicol, an impoverished farming area of more than five million facing the Pacific Ocean which felt the initial force of the typhoon.

Manila office worker Karen Luna said her family spent a miserable night at home in Bacoor town adjacent to the capital with no power or tap water supplies.

"At first light I ordered my child to fetch water, so I was able to bathe before going off to work, using half a pail," Luna told AFP.

She said the neighbourhood was forced to use candles overnight Wednesday and could not log onto the Internet, while food was eaten quickly so it would not waste in the fridge.

"We have been feasting on crab and prawns since yesterday after cooking everything inside the refrigerator. We were worried the food would spoil," she said.

Across Manila, streets remained littered with fallen trees, branches and electrical posts as repairmen struggled to restore power services.

The Philippines is hit by about 20 major storms a year, many of them deadly. The Southeast Asian archipelago is often the first major landmass to be struck after storms build above the warm Pacific Ocean waters.

Rammasun was the first typhoon to make landfall since this year's rainy season began in June.

It was also the first major storm since Super Typhoon Haiyan devastated the eastern islands of Samar and Leyte in November last year, killing up to 7,300 people in one of the Philippines' worst natural disasters.

Those areas were largely spared from this week's typhoon.