The death toll from massive flooding in Thailand has risen to 12, with more than 640.000 families affected, authorities said on Sunday.

Five people drowned in southern Songkhla, three in Pattani, two in Narathiwat and one each in Phatthalung and Yala provinces, the Bangkok Post reported on Sunday, citing the Department of Disaster Prevention and Mitigation.

Rescuers and municipal workers dug through debris and began repairing roads in Thailand's southern economic hub as flooding in southern provinces remains serious.

Hat Yai, the economic hub of southern Thailand and the main destination for tourists from Malaysia, is slowly returning to normal.

City workers began clearing flood debris and repairing streets in the city to clear surfaces for traffic after rainwater flooding and overflowing drains paralyzed the city.

The overall flood situation in Hat Yai Municipality has improved, according to the municipality.

Flooding, however, continued in most areas in the region with parts of major roads still submerged.

Motorists are advised to check updated information from the provincial and highway department for safety reasons.

Weather authorities today warned of heavy rain, strong winds and rough seas in Songkhla and Narathiwat provinces, while torrential rains are expected in Phatthalung and Yala provinces. /AA