Rescue workers remove a dead body from a collapsed house after a landslide caused by heavy rainfalls in Seoul July 27, 2011.[Photo/Agencies]

SEOUL - At least 53 people are dead or missing after the heaviest rains in a century lashed the South Korean capital Seoul and surrounding areas, officials said on Thursday, with damage expected to run into hundreds of millions of dollars.

More rain battered the mountainous region on Thursday prompting authorities to draft in the military to help with rescue and clean-up operations.

"We have asked the Defence Ministry and police to help because the torrential rains and floods need to be controlled in cooperative nationwide system," an emergency services spokesman said.

More than half a metre (19.5 inches) of rain has fallen in the Seoul region since late Tuesday, the weather bureau said, in the heaviest deluge for July since 1907.

Landslides were reported around the capital and streams turned into raging torrents, flooding low-lying areas and swamping thousands of cars.

Yonhap news agency said a rescue operation was underway at a Buddhist monastery after a landslide trapped four people.

Some bridges over the main Han River, which runs through the centre of the city, were closed. Train services were also disrupted.

Authorities said on Thursday more than 4,500 people had been forced out of their homes and many houses were without power.

In the worst single accident, a mudslide smashed into three small hotels in the mountain resort of Chuncheon, about 100 km (60 miles) east of Seoul, killing 13 people on Wednesday.

Emergency services put the death toll at 41, with 12 people missing.

Power outages hit Seoul again on Thursday, including a cut in a business district, but the financial services industry and market trading were not affected.

The share price of insurers steadied after tumbling as much as 6 percent on Wednesday, but premiums are expected to rise causing further financial pain for homeowners already stung by rising inflation.

"Although their stocks recovered some of the losses from yesterday, the news flow doesn't seem positive for the time being for insurers," said Sung Yoon-hoon, an analyst at Hana Daetoo Securities, adding he expected costs to snowball.

The Financial Supervisory Service, the country's financial regulator, estimated the bill for car damage alone would be about $25 million.