SINGAPORE - A video of two bus commuters quarrelling has been making the rounds on social media.

In the almost six-minute long clip, a man and a woman are seen hurling vulgarities at each other while on SBS Transit's bus service 502, on its way to the Suntec City Convention Centre on Sunday evening.

The altercation apparently started when the man overheard the woman calling the Chinese bus driver stupid.

"He is not stupid, understand this?" the man is heard as saying.

Pointing his finger at the woman, he calls her derogatory names, and tells her to go back to her own country.

The woman tries to explain herself, but is repeatedly cut off.

After about a minute, the bus driver pulls the duo apart and tries to calm them down, but the man starts his furious rant again when the double-decker bus gets moving.

He even walks over to where the woman is sitting and continues spewing insults, calling her a "moron" and an "idiot".

Meanwhile, the woman retorts that the man has no manners. She adds that though she is not Singaporean, her son is currently serving National Service.

Eyewitness Jona Acosta Carbonel, who had boarded the bus on Orchard Road, filmed the altercation on her mobile phone and posted it on Facebook.

The video has since gained almost 260,000 views and more than 5,300 shares.

"(The other passengers) all just sat there and tried to ignore it," said Ms Carbonel, adding that like her, many were shocked at the outburst.

The exchange ended when another passenger tried to mediate and left the bus together with the woman near Suntec City, said Ms Carbonel, 30, a Filipino domestic worker here.

She had posted the video because she wanted to know if any of her Filipino friends recognised the woman, who appeared to be from the Philippines.

As for the man, Ms Carbonel told The Straits Times he looked like he was drunk.

"I feel sorry for him. Maybe he just want to stand up for the driver, but he did it in a wrong way by losing his temper," said Ms Carbonel.

SBS Transit has yet to respond on whether they are investigating the matter or have reported it to the police.