A Saudi rights group said Monday it is investigating a video appearing to show a local man brutally beating up an Asian worker in the kingdom that hosts millions of foreign labourers.

The video posted online shows a man dressed in the traditional Saudi white Thawb cloak, slapping, lashing and kicking an Asian man.

The National Society for Human Rights is "investigating the issue," its head Mefleh al-Qahtani told AFP. The semi-governmental organisation would demand the perpetrator be punished if the case is confirmed.

"We do not have enough details about the identity of the man, or on where the incident took place," he said.

But another rights activist said the Saudi man lives in Riyadh and had punished the worker for having spoken to his wife.

A third man is heard in the 1:53-minute video, apparently while filming, as the victim was pushed to the floor by his attacker, in what appeared to be a living room.

The worker screamed repeatedly as the man flogged him.

It is not clear when the video was first posted online, but one copy on YouTube dates back to Friday.

International human rights groups frequently accuse the oil-rich kingdom and other Gulf monarchies of mistreating foreign workers, especially South Asians who make up the bulk of low-paid labourers.