Eighteen people were injured during a Christmas party when the top floor of a restaurant collapsed in Thailand.

The group of 50 employees from a local insurance company had gathered for the holiday celebrations at the eatery in Phrae province on December 24.

Before shutting up shop for the Christmas break, they crowded into the centre of the room for a group photo, but the flimsy wooden planks could not bear their weight.

The floor gave way, sending the terrified revellers crashing from a height of around 10 feet.

Police Colonel Pongpeera Karaket, Muang Phrae police chief, said: 'Eleven of the 18 people injured were sent to the Phrae Hospital. Three were taken to the Phrae Christian Hospital, and four to the Phrae-Ram Hospital.

Restaurant proprietor Suwit Sombat said the customers were eating on the other side of the restaurant before the accident happened.

He added that they fell because all of their weight was concentrated at one point.

He said: 'I was in another room when the floor collapsed. If I had seen them gathering, I would have warned them not to do it. Normally, the floor can only handle around 30 people.'

Diner Wannee Intajuang said: 'We were all standing together to take the group photo. Suddenly, we heard the wood creaking and the floor gave way.

'The person standing next to me fell, but I managed to back away at the last second. I was so shocked because I didn't expect this to happen. I want the store to take more safety precautions.'

The shop was a wooden house raised on stilts. Police said some of the beams supporting the floor had been eaten by termites. The planks were found to be around 1.5 centimetres thick.

Officers said they will be questioning Suwit to see if he is liable for the accident.