A multi-million pound oyster farm and hotel burned down on Friday after workers accidentally set fire to mosquito spray.

Sinmana Farmstay - a floating sea resort which allowed guests to catch the molluscs - was preparing for big tour group arriving today (Sat).

Workers sprayed the pier style building with a thick fog of flammable liquid - reportedly a mixture of oil, diesel and gas - which went up in flames at 5pm.

Fire on the first floor engulfed artificial grass and the blaze spread throughout the building off the coast of Surat Thani, southern Thailand at 5pm yesterday (Fri) evening.

Rescue crews arrived by boat and for several hours battled the inferno, which caused 20 million baht (620,000USD) in damage.

Owner Somchai Sinma said: ''Workers were spraying mosquito spray because a big tour group was coming today.

''A spark ignited the spray and it quickly spread. They couldn't put out the flames and they spread very quickly on the artificial grass.''

The 200 square metre farm and hotel allowed guests to learn about oysters, catch them and eat them in the Bandon Bay.

Nobody was injured in the incident.

Somchai said he would now begin trying to repair the building.