Gusts of more than 100 kilometres per hour were recorded, with rain lashing down, as the Hong Kong Observatory hoisted a "Number 8" storm warning in the early hours -- the third highest level.
As the typhoon skirted the city about 240 kilometres to the southwest, the observatory downgraded the warning in the afternoon to "Number 3", indicating strong winds.
Damage was limited with no landslides reported, but the winds blew down a number of trees and signboards, and left bamboo scaffolding swaying.
Ferry services to outlying islands and mainland China were halted in the morning, stranding passengers at various terminals.
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A government spokesman said six people were treated in public hospitals for storm-related injuries and there were six cases of minor flooding.
Overnight the government opened 17 temporary shelters, with dozens of people seeking refuge.
The city's streets were noticeably quiet in the morning, with many workers staying home as businesses and schools were shuttered.
But as the storm passed more people could be seen venturing out, umbrellas hoisted, as the city returned to normal.
Utor, which is packing winds of 155 kilometres per hour near its centre, was heading towards the coast of Guangdong province in southeast China at 16 kmh.
It was predicted to make landfall today night or tomorrow morning, according to China's state news agency Xinhua.
Waves as high as 11 metres were expected in the north of the South China Sea, it reported, with disaster prevention teams requested for the area.
The storm earlier swept across the Philippines, flattening houses and causing flash floods and landslides.