Three people were injured after they were hit by a 50kg shop sign that was blown down by strong winds in Thailand.

The three men were carrying products into a storage room next to a curtain shop in Chachoengsao province on April 21 when the unstable old signage fell on top of them.

Chachoengsao police arrived and found the workers seriously injured and bleeding from their heads after the heavy billboard struck them. Officers identified them as Heman Sowana, 27, Somphon Korkaew, 51, and Kamol Bunnakosol, 63. Paramedics gave the patients first aid before rushing them to the Buddhasothorn Hospital and Kasemrad Hospital.

Police said the sign weighed about 50 kilograms, and was 1.2 metres long and 2.3 metres wide. It had dents from the impact of hitting the pavement, and closer inspection found that its iron welds had rusted over.

Eyewitness Kanchit Phukhrongthung said: 'There was a strong wind, and it looked like rain at the time of the incident. Suddenly, the nameplate of the shop at the top of the building swayed. I heard a loud noise and looked up to see that the iron sign was falling. I tried to warn them to run away, but the sign fell so quickly because of its weight.'

Officers have taken the shop owner to the Chachoengsao Provincial Police Station for questioning. They added they will interview the injured men once their conditions have improved to see if the workers want to take legal action.