Police arrested a truck driver after a 29-year-old woman was killed and her four-year-old son was injured in a Lok Ma Chau traffic accident today.

They were reportedly knocked down by a truck on Ho Sheung Heung Road at about 11.55am.

The mother was certified dead at 12.32pm in North District Hospital, while her son was sent to Prince of Wales Hospital with multiple injuries.

The 48-year-old male driver was arrested for dangerous driving causing death.

Witnesses should call Police on 3661 3800 or 3661 3860.