BANGKOK?Thai hospital staff said they were forced to evacuate patients on Monday as the kingdom's flooding crisis, which has killed more than 100 people in three weeks, spread to the south.

Na Thawi district hospital in Songkhla province was forced to close and transfer 37 patients to another medical center after the area was hit by early morning flash floods, director Suwat Viriyapongsukit said.

"Floods have reached the building at around one meter high and we cannot operate," he told AFP.

Authorities say the nationwide floods, which began on October 10, have affected about five million people and left 101 dead, although until now they were mostly in central, northern and eastern parts of the country.

The south is facing heavy rain this week and officials warned of further flash floods in the region, although the problem has subsided in some areas further north.

Tens of thousands of people across the country have sought medical treatment, mostly for itchy skin, common colds and stress, while homes have been submerged and farmland and cattle destroyed.

This week the government is expected to start paying compensation to more than 600,000 households affected by the floods, which are expected to cause a 0.3 percent drop in Thailand's 2010 gross domestic product.

Bangkok has been on standby with thousands of sandbags and pumps as flood water from the north runs downstream and could coincide with high tides.

So far the capital has avoided major flooding, although more than 1,000 homes along the Chao Phraya river have been partially submerged.