The Observatory cancelled all tropical cyclone warning signals at 1.20am on Friday as Typhoon Toraji weakened and the threat to Hong Kong receded. .

However, the Observatory said it's still monitoring another tropical cyclone, Tropical Cyclone Usagi.

It said Tropical Cyclone Usagi is currently forecast to cross the Luzon Strait on Friday morning and enter within 800 kilometres of Hong Kong.

It said it's expected to stay more than 500 kilometres from Hong Kong, posing little direct threat to the SAR.

It will then move northeastward toward the Ryukyu Islands and to gradually weaken.