Three people, including a Hong Kong man and his sister, have died in a road accident in Haifeng county, Guangdong, after their car collided with a truck. Another Hong Kong woman, the dead man's sister-in-law, was seriously injured and receiving treatment in a local hospital. Officers from Hong Kong's Economic and Trade Office in Guangdong had been in touch with her to offer help. A police spokesman in Haifeng said the car was carrying six passengers - three Hongkongers and three from the mainland - when it collided with a truck carrying concrete on Friday. Two died at the scene, while the third fatality - a mainland woman - died later in hospital. The other two passengers from the mainland - both teenagers - were also in hospital. It was unclear if all six were related. The dead man was believed to have been driving the car at the time, police said, while his sister was the front-seat passenger. Both of them were around 40 years old. Chief immigration officer Chu Kwok-kwong said immigration officers - along with some family members - arrived at the hospital at midnight to help the injured Hong Kong resident. 'We will help according to the relatives' wishes, whether to cremate the bodies or to take them back to Hong Kong,' he said. He said whether or not the injured woman could return to the city for medical treatment would depend on her condition. Hong Kong residents who need help while away may call the Immigration Department's Assistance to Hong Kong Residents Unit on its 24-hour hotline (852) 1868.