YASOTHON-Huge home-made rockets tore through the clouds Sunday as folk bands played for crowds at a rollicking festival in rural Thailand aimed at encouraging the beginning of the monsoon season.

Known as "Bun Bang Fai", the annual rocket festival celebrated in the northeastern region of Isaan is aimed at prodding gods into unleashing rain ahead of the rice-farming season.

The raucous event, which involves religious processions, mud wrestling and plenty of booze-fuelled dancing to Thai country music, also has a competitive edge.

Teams tour the rural region and compete to see who can send their home-made rockets highest.

On Sunday around 500 people gathered in a field in Yasothon province - the festival's flagship venue - to watch crews haul massive rockets made of blue pipes and bamboo onto towering launch pads.

"It takes about ten people to make these rockets," explained Asan Luamakam, a 48-year-old train station worker taking part in the competition.

"I don't think it's that dangerous... we've been doing this so long, we know what we're doing," he added.

Minutes later one rocket malfunctioned and exploded before take-off, setting a patch of grass on fire.

But it was only a momentary distraction and revellers cheered as other rockets shot into the sky, disappearing into the clouds and leaving plumes of white smoke in their wake.

Judges assess the rockets based on how dramatically they take off, how far they fly and how pretty a smoke trail they leave.

The festival - which produced about one minute of rain in the afternoon during launching - is also celebrated in neighbouring Laos, which has close cultural and linguistic links with Thailand's northeast.

"I've made rockets for 38 years and I'm a five-time champion," said 58-year-old Baramee Gonchuarakan, a Yasothon native.

"We do this because it's our way of life."