BANGKOK (REUTERS) - Businesses blocked doors with sandbags and bricks on Tuesday (Aug 7) as Thailand's south-western Phetchaburi province braced for flooding over fears that a dam in the area could overflow.

Local media showed residents in Phetchaburi, 168km from Bangkok, laying bricks outside shops and buffering entrances to banks with sandbags.

Thailand is in the middle of its rainy season which often generates flash storms. The Meteorological Department said more storms are expected between Tuesday and Thursday (Aug 7-9).

Thailand suffered its worst floods in half a century in 2011. The floods killed more than 900 people, crippled industry and dented economic growth.

Officials said they are confident that water levels at the Kaeng Krachan Dam and any water run-off can be managed.

"Four districts could be affected... The governor and local administration are preparing sandbags and water pumps," Interior Minister Anupong Paochinda told reporters in Bangkok on Tuesday.

Prime Minister Prayut Chan-o-cha is due to visit Phetchaburi on Wednesday.

Tourists visiting Phetchaburi, which is near the Gulf of Thailand and is home to many seaside resorts, will be warned.

"Operators and resort owners are aware of the situation. We will send an alert to tourists," Tourism Minister Weerasak Kowsurat told reporters.

In neighbouring Laos, 31 people have been confirmed dead and 130 are still missing after part of a hydroelectric project in the southern province of Attapeu collapsed last month.

The company building the dam said heavy rain and flooding caused the collapse.