Police said they're investigating a fatal traffic accident in Sheung Shui on Friday night in which a 57-year-old woman died.

They said that at about 8.40pm, a private car driven by a 26-year-old man was travelling along Sha Tau Kok Road - Lung Yeuk Tau towards Sha Tau Kok.

They said that when the vehicle was approaching Kwan Tei North Tsuen, it reportedly knocked down the 57-year-old woman who was crossing the road.

They said the woman sustained head injuries and was certified dead at 9.23pm in North District Hospital.

Police said the private car driver was arrested for dangerous driving causing death, and is being detained for further enquiries.

They said they're investigating the accident and have appealed to witnesses to contact investigating officers on 3661 3800 or 3661 3858.