The Observatory said it will assess whether it is necessary to issue the Strong Wind Signal No 3 on Saturday afternoon.

Acting senior scientific officer Chong Sze-ning said the Standby Signal No 1 will remain in force until at least Saturday noon.

She said Severe Tropical Storm Wutip was estimated to be about 730 kilometres southwest of Hong Kong as of 5pm and forecast to move north slowly, skirting the western coast of Hainan.

"According to the present forecast track, Wutip will turn northeastwards gradually," Chong said.

"It will make landfall near Leizhou Peninsula during the day [on Saturday] and then move across the vicinity of the Guangdong-Guangxi boundary."

Chong said the issuing of a higher signal will depend on Wutip's intensity, distance from Hong Kong and local wind changes.