Firefighters were called to Regal Crest on Robinson Road shortly before 11am.
They found an unconscious woman in a guest bedroom, and a man and a woman who had collapsed in the ensuite bathroom of the master bedroom.
All three had inhaled smoke and two also had burns to their hands.
“When firefighters entered the scene, they found that the entrance was blocked by a sofa, and it was relatively difficult for them to enter the flat. They later found that the doors of the corridor and master bedroom were locked from inside,” said assistant divisional officer Mo Shan-hoi.
“Firefighters found two origins of fire in the master bedroom,” Mo added.
Around 50 people fled to safety from the building during the fire.
Police said they were also investigating the blaze, with government laboratory and forensic staff heading to the scene to look for evidence.
