The fire started at the top of the 42-story skyscraper, which was nearing completion, and engulfed the jetty.
Hong Kong firefighters battle a massive blaze at a high-rise building under construction in the Kowloon district, forcing some nearby apartment blocks to be evacuated.
Officials said the fire broke out at 23:11 (15:11 GMT) on Thursday in the heart of densely populated Tsim Sha Tsui, a popular shopping and tourist district next to the harbor.
It eventually escalated to the fourth level of severity on a five-point scale and about 130 people living in three nearby buildings were evacuated early Friday amid fears the fire would spread.
Several floors of the structure – including scaffolding – were on fire and burning debris floated in the air. Some fell to the ground.
At around 8am (00:00 GMT), the government said that while the fire was under control, crews were still fighting the blaze.
Police said six neighboring buildings, including the three where the evacuation took place and the Sheraton Hong Kong Hotel & Towers, also caught fire, but the flames were extinguished. No casualties were reported.
The fire, which was clearly visible in the night sky on the other side of the harbour, drew crowds of spectators.
The 42-story skyscraper that caught fire was nearing completion and part of a $6 billion Hong Kong dollar ($764 million) redevelopment project by developer Empire Group.