A high-rise building under construction in Hong Kong erupted in flames and was still burning hours later, with some nearby residential blocks evacuated early Friday after the fire threatened to spread.

Officials said the fire started at 11:11 pm local time Thursday in the heart of Tsim Sha Tsui, a busy shopping and tourist district on the city's harbour.

No casualties had been reported early Friday, while 130 affected residents had been relocated to a safe distance, police said.

Flames were first spotted near the top of the building, with the blaze clearly visible across the harbour and sending sparks raining down onto neighbouring streets.

Around an hour later, the fire had spread down the length of the building and was approaching street level, where hundreds of onlookers had gathered.

Large pieces of debris -- apparently from the site -- were visible on the ground, and an acrid smell permeated the air, an AFP reporter on the scene said.

Flames were seen on the roof of an office tower across the street at around 3:30 am, prompting fears of a wider fire in the densely built area.

Police said five buildings in the surrounding area had reported fires, though some had been quickly extinguished.

The 42-storey building was to house the historic Mariners' Club and a new hotel, according to the website of its developer, the Empire Group.