"A female tour group member allegedly had a dispute with her [female] group leader from the mainland as she did not want to make a purchase in the shop," a police source said.

The man joined the argument before a scuffle between the three broke out.

"Four men allegedly rushed in and attacked the mainland man," the source said.

The attackers fled before police arrived and the man was taken to Queen Elizabeth Hospital in Yau Ma Tei. He was in a critical condition last night.

A police spokeswoman said he was among three people arrested on suspicion of fighting in a public place.

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The female group leader, 32, who was also arrested, complained of suffering injuries to the face and hand and was taken to the same hospital.

The third suspect, 53, was the female tour member involved in the dispute.

In the afternoon, officers from the Kowloon City district crime squad were poring over security camera footage to collect evidence and none of the suspects had been charged.

Travel Industry Council executive director Joseph Tung Yao-chung said such violence would damage the city's reputation as a shopping paradise.

"We have zero tolerance for such violence," he said, pledging that the council - the industry's regulatory body - would follow up the case after police complete their investigation.

He appealed to tourists, tour guides and group leaders to solve disputes through discussion instead of violence.

It is understood that the tour group arrived from Shenzhen on Sunday for a three-day trip including visits to Ocean Park, The Peak and Repulse Bay.