There are reports that some residents were trapped in the building, and police say 279 people are still missing. BBC reported.
More than 760 firefighters were deployed to tackle the blaze on Wednesday afternoon, with pictures showing flames and thick clouds of grey smoke billowing from the towers, dominating the city's skyline.
Three men have since been arrested on suspicion of manslaughter connected to the fire, according to local media reports, and an investigation has been launched.
The blaze broke out at the Wang Fuk Court housing complex at 14:51 local time (06:51 GMT) and was classified as a level five - the highest in severity - by the fire department at 18:22.
The cause is unknown, but the flames are believed to have spread quickly through the bamboo scaffolding that covered the outside of the buildings, which were undergoing renovations.
Among those hospitalised, 45 are in a serious condition. The injured were sent to hospitals in various districts.
Firefighter Ho Wai-ho, 37, was among those killed in the blaze. He was found collapsed at the scene about 30 minutes after contact with him was lost.
"I extend my deepest condolences to the deceased and my heartfelt sympathies to their families and the injured. We will provide all possible support," he said.
The fierce heat of the blaze, as well as dangerous debris has hampered rescue efforts.
"The temperature inside the buildings concerned are very high, so it's quite difficult for us to enter... and go upstairs to conduct firefighting and rescue operation," said Derek Armstrong Chan, the deputy director of fire services.
The fire has yet to be extinguished and officials have said they were unsure when it would be.
Wang Fuk Court was built in 1983 and is made up of eight tower blocks that provide 1,984 apartments for some 4,600 residents, according to a 2021 government census. Seven of the towers have been affected by the fire.
