A bus conductor in Sichuan province has been strongly criticized online because she refused to give her seat to an old woman.

The passenger in her 70s took the seat of the conductor on the overcrowded bus No 309 from Wenjiang, a district of Chengdu, to Baihua Central Bus Station in downtown Chengdu, around 11 am on Sunday.

"She told the conductor she was sick and had a lot of luggage, and she wanted to sit for a while. But the conductor insisted the old woman get up and find a seat by herself," a passenger surnamed Li told West China Metropolis Daily.

As the conductor kept asking the old woman to give up the seat, other passengers became indignant and had an altercation with the conductor. The bus driver came to the conductor's aid by stopping the bus three times, claiming something was wrong with the bus. Only after being persuaded by passengers did he restart the bus, according to a video uploaded on the Internet by a passenger.

Guanghua Bus Transport Co Ltd, which oversees bus No 309, is investigating the case.

An official surnamed Zhu told West China Metropolis Daily the company would punish the people involved if what was shown in the video was true.