Police on Sunday said they had arrested the mother of a four-year-old boy who died after she reportedly gave him medication.

Officers say the boy fainted at a flat on San Ma Tau Street in To Kwa Wan shortly after noon on Sunday.

The child was sent to Queen Elizabeth Hospital, where he was certified dead at around half past seven in the evening.

The 37-year-old mother was arrested on suspicion of mistreating or neglecting her son.