The Hong Kong Observatory said the Standby Signal No 1 will remain in force at least until Sunday morning, unless tropical cyclone Kajiki intensifies significantly or adopts a more northerly track.

The weather watchdog said the storm will be closest to Hong Kong on Saturday night, skirting around 500 kilometres to the south of Hong Kong.

It said Kajiki will continue to intensify, bringing about occasional strong winds to the southern part of the city.

The Standby Signal has been in force since 9.40pm on Friday.