The Observatory on Tuesday said the T1 signal will remain in force until at least 10pm.

It said Severe Tropical Storm Man-yi had continued to weaken, and was closest to the SAR, skirting within about 400 kilometres of the city. It issued the T1 on Monday morning.

The Observatory warned that under the combined effect of spring tide, the northeast monsoon and Man-yi, coastal water levels would will be higher than normal between 10 pm and midnight on Tuesday, and warned of possible minor flooding in some low-lying coastal areas, and urged the public to take care.

"There will be swells," it added. "Members of the public should stay away from the shoreline and not engage in water sports."