The attack happened during the morning commute on a busy bus route. Picture: John Appleyard

The woman, in her early 20s, was shocked to find her hair being lopped off by two passengers sitting behind her.

The incident occurred around 9:40am on the 339 bus, which travels from Clovelly in the city’s Eastern Suburbs to the city.

A witness — who did not want to be identified — said a woman with long dark hair, started crying hysterically when the bus was at Moore Park.

“Finally she told people what was happening, that they had cut a chunk out of the back of her hair,” the witness told Fairfax Media.

“It was so creepy.”

The passengers then spotted the man and the woman who had been behind her on the street. They had gotten off at the stop before.

The witness said that the bus driver pulled over near Cleveland Street and Anzac Parade and began chasing the couple. However, it is not known if the two perpetrators were caught.

A NSW Police spokeswoman said they did receive a call about the incident, however the woman did not want to speak to them at the time, reported Fairfax.

The witness explained that he noticed the couple the moment he got on the bus in Clovelly due to their bizarre behaviour.

“She was sitting on his lap sucking her thumb. I thought, ‘That’s a bit weird’. I moved so I wasn’t near them,” he said.