Police using teargas stormed a house and arrested a man who shot dead his elderly father at their home in Surat Thani on Tuesday, ending a 12-hour siege.

Around 6.30pm on Tuesday, police then fired tear gas into the house where murder suspect Suriya Saengsawang was hiding.

Ten minutes later the team stormed into the house.

They arrested Mr Suriya and took a .38 pistol from him. The suspect was very agitated. He was taken to a hospital, where staff calmed him down.

Mr Suriya, said by his sister to be mentally unbalanced and refusing to take his medication, shot dead his father Sophon Saengsawang, 74, in front of their home about 4.30am on Tuesday.

His sister said  Mr Suriya had been digging up the soil in front of the house, and his father told him not to do that. Suriya had been upset, grabbed his father's gun and shot him in the head. He then ran into the house.

Police arrived and surrounded the house. They brought in a psychologist to try and persuade the man to come out.

He remained inside the house, with the gun, until Tuesday evening when police forced their way inside.