The city's Department of Construction said it had instructed Hanoi Metro Company (HMC) to conduct a comprehensive review of similar structures at all stations on the Cat Linh-Ha Dong line.
The order follows an incident in which part of the plaster surrounding the station's name sign fell onto a road and struck a bus. No injuries were reported.
According to preliminary findings, the plaster's bonding strength had deteriorated over time and may have been affected by vibrations generated during metro operations.
To prevent similar incidents, HMC has been instructed to hire an independent consultant to inspect and assess comparable structures throughout the line.
Based on the results, the operator will be required to implement permanent repairs to ensure safety and maintain the appearance of the stations. Repairs at the affected site must be completed by July.
The department has also proposed immediate repairs to ageing or potentially unsafe structures on both the Cat Linh-Ha Dong line and the elevated section of the Nhon-Hanoi Station metro line.
HMC has been asked to complete documentation needed to include repair and maintenance works in the city's 2026 urban railway infrastructure maintenance programme.
Officials said timely inspections and repairs were essential to ensuring the safe operation of Hanoi's metro network and reducing risks to passengers and road users.