The Standby Signal Number 1 will remain in force for "most of" Friday, the Observatory said, although it did not rule out the chance of a higher signal in the evening.

The forecaster said Wutip, which has intensified into a severe tropical storm, took a slightly westward track away from Hong Kong.

It will assess the need to issue the Strong Wind Signal Number 3 between Friday night and Saturday morning.

As of 8am Friday, the storm was about 720 kilometres southwest of the city.

It is forecast to skirt the western part of Hainan Island on Friday before turning northeast towards inland Guangdong.

As it edges closer to the vicinity of the Pearl River Estuary over the weekend, winds are expected to gradually strengthen across the territory on Saturday, coupled with occasionally heavy squally showers and swells.