A traveller from Hong Kong has died in a traffic accident in Xinjiang, while three other tour members were injured and hospitalised.

The Travel Industry Authority (TIA) said the tour, operated by Travel Circle International, was involved in a car crash on Wednesday.

The tour group of 20 was on an 18-day trip to both the northern and southern parts of Xinjiang.

"On the 8th day of the trip, the travellers were split into groups of four to get on vehicles to tour the Duku Highway," the agency said in a statement.

"Unfortunately, one of the vehicles was involved in a traffic accident, resulting in varying degrees of injuries to the four on board."

The agency said one of the travellers died on Wednesday night at a local hospital. The three others were sent to hospital, accompanied by their tour guide.

The TIA said it's reported the case to the SAR's Immigration Department and the relevant authorities in Xinjiang.

It's understood that Travel Circle International immediately sent staff to Xinjiang to offer support, and the remaining tour members continued their journey with another Xinjiang guide.

The authority said it's saddened about the case, and will work with the travel agency to render all possible assistance.

The Immigration Department, for its part, said representatives from its Beijing office have immediately travelled to Xinjiang to offer help.