The National Centre for Hydro-Meteorological Forecasting (NCHMF) said the storm was centred over Guangxi at 1 pm, with maximum sustained winds of 50-61 kph and gusts of up to 75 kph, moving northeast at about 10 kph.
The tropical depression is forecast to continue weakening into a low-pressure area and is no longer expected to have a direct impact on Vietnam.
However, strong winds and rough seas are expected to persist over the northern Gulf of Tonkin, and the weather agency urged vessels to continue monitoring marine weather forecasts.
Despite the storm's weakening, heavy rain is forecast to continue over parts of Lai Chau, Son La, Lao Cai and Quang Ninh over the next several hours, raising the risk of flash floods and landslides.
Rainfall of 20-40 mm, with isolated totals exceeding 70 mm, is forecast in Lai Chau and Lao Cai, while Son La and Quang Ninh are expected to receive 10-20 mm, with some areas recording more than 50 mm.
The weather agency maintained a Level 1 natural disaster warning for flash floods and landslides and urged local authorities to inspect vulnerable areas and drainage bottlenecks to minimise risks.
Between 1 pm on July 4 and 1 pm on July 5, rainfall reached 325.4 mm in Mong Cai in Quang Ninh, 284 mm in Nam Pam in Son La, 159 mm in De Xu Phinh in Lao Cai, and 138.6 mm in Phu Nam Sap in Lai Chau.