Police are investigating suspected arson after three people were left unconscious and another was injured in a fire at a subdivided flat in North Point in the early hours of Wednesday.

A man who reported the fire to police was plucked from a balcony at Ying Wong House on King's Road by firefighters, while another man and two women were rescued unconscious from inside the flat and taken to hospital.

The 35-year-old reportee and one woman aged 29 were sent to Eastern Hospital, while a 22 year-old man and a woman aged 32 were sent to Ruttonjee Hospital.

Police said accelerants were found at the scene, and that the case has been passed on to the Regional Crime Unit of Eastern District.

The fire was reported at about 2.45am and extinguished a little over half an hour later.