Locals started their annual Songkran festival water fights today in Thailand.

Footage shows residents in a pickup truck as passersby hurl water at them in Si Sa Ket province this morning April 12.

The Buddhist festival Songran, which takes place every year from April 13 to April 15, sees the country's businesses close down while inhabitants splash each other with water to bring prosperity for the coming year.

It's also a way to cool off during the hottest month of the year when temperatures reach 40 degrees Celsius.

However, the once-sedate festival has spawned into an alcohol-fuelled orgy of round-the-clock water fights across the country's major cities, with hundreds of thousands of tourists joining in the chaos.

Ministers have urged locals not to drink and drive while officials in Bangkok have designated different areas of the city according to the intensity of the activities.