The fire, spanning seven blocks of a high-rise housing complex, is still yet to be contained almost 22 hours after it broke out in the northern Tai Po district.
Police have arrested three construction company executives, two directors and one engineering consultant on suspicion of manslaughter.
Rescue teams have begun searching apartments for survivors in four of the towers where the fire has been extinguished, and the death toll is expected to continue to rise.
Another 45 people remain in critical condition in hospitals.
Wang Fuk Court is a 2,000-unit residential complex made up of eight blocks in total, and was undergoing renovations at the time of the fire.
Experts say bamboo scaffolding likely allowed the fire to spread quickly between buildings.
John Lee, Hong Kong's chief executive, says the government may postpone a 7 December general election, calling the blaze a “massive catastrophe.”
This is Hong Kong’s deadliest fire in more than six decades, with at least 44 people confirmed dead and 279 still unaccounted for.
The current toll matches that of the August 1962 blaze in Sham Shui Po, which killed 44 people and left hundreds homeless after around 50lbs (22.7kg) of fireworks stored on-site caused the flames to race up the building, according to the South China Morning Post.
Other major tragedies include the 1996 Garley Building fire in Kowloon, which killed 41 people and injured 81.
