This is the shocking moment a furious Buddhist monk punched a driver who accidentally killed his sister in a horror crash in Thailand.

Grieving Sirachon Phongkaew, 20, could not contain his anger when motorist Kan Ketmahasak, 52, appeared at his sister's funeral in Rayong province on December 29.

Kan had lost control of his pickup truck two days earlier while driving in front of the Ban Khai School. He crashed into a motorcycle when he sped across lanes, killing two young women - including Sirachon's sister Natthaphon, 15.

The repentant driver had turned up to offer his condolences at the funeral, but received venomous stares and a painful welcome instead.

Footage shows Sirachon in his orange robe unleashing blow after blow on Kan, who was wearing an armsling, to vent his rage. He was heard screaming 'Why did you kill my sister?' as he rained punches on the suspect.

Funeral-goers stepped in between the pair to defuse the situation, before police escorted Kan from the premises. Relatives continued hurling condemnations at him as he marched through the crowd with his head hanging in shame.

Speaking to local media, Kan said: 'On the day of the accident, the car went out of control. I was driving on the left lane and moved to my right, but it glided across the island in the middle of the road.

'I didn't mean for the accident to happen. I am sorry to the family and I admit my guilt. An apology wouldn't be enough. But I want to tell everyone that it was not intentional.'

Police said that Kan had been questioned on suspicion of causing the death but he has not been charged with any offence.