This is a bizarre moment a two-year-old boy refused to open a car door for his grandfather, causing police and a locksmith to arrive to help.

Pairoj Thipmhad, 47, took his grandson with him to a houses while he went to deliver packs of water in Songkhla, southern Thailand on Monday (March 30) morning.

At one of the homes, he left Adew Japakiya in the locked car while he dropped off the supplies.

But when he came back to the car he could not open the door. He tried to talk to his grandson to unlock it for him but the boy refused and he had to call the police.

The police came to the scene with a locksmith who helped to unlock the door and release the boy.

The relieved grandfather said his grandson always play like this but he would normally unlock the door - but not this time.

He said: "I always bring him along with me when I deliver the water and he always plays with the lock when I am away.

"He usually unlocks it when I come back but this time he playfully refused and I worried that he might be suffocated inside before I had the chance to convince him to unlock the doors.

"Fortunately, there was enough time for the police and locksmith to arrive before he had any problems.''

The boy did not seem to be phased by the incident and was only surprised by the number of people gathering around the vehicle.