The Hong Kong Observatory stated that heavy rains from Typhoon Kompasu may flood low-lying areas, and residents should be aware.
The winds sustained by the typhoon were 83 km/h (51 miles/h) with gusts of up to 101 km/h (63 miles/h).
The observatory stated that winds were expected to weaken gradually in the afternoon.
According to the observatory, the typhoon was forecasted to travel across the northern part of the South China Sea towards China's southern island province Hainan before making landfall in northern Vietnam.
Officials said that Kompasu had earlier caused flash floods and landslides in the northern Philippines. This left at least 11 dead and seven others missing.