The Observatory says the Strong Wind Signal No 3 will remain in force until at least 6pm on Wednesday.

The forecaster said at noon, tropical storm Mulan was about 450 kilometres southwest of Hong Kong and was moving away from the SAR.

It said there are still strong winds over many places, adding that it would issue the Standby Signal No 1 when local winds show signs of weakening.

It urged the public to stay alert as there will still be occasional gale force winds over the offshore waters and on high ground, while the outer rainbands of Mulan will occasionally bring violent gusts.