Le Anh Quan, vice chairman of the Haiphong People's Committee, has instructed police to work with military, transport and local authorities to investigate the cause of the accident, which occurred on June 14.
The city has also ordered a comprehensive review of passenger transport operations in the bay, particularly wooden tender boats used to carry tourists.
Local authorities in Cat Hai Special Zone have increased inspections and safety guidance for boat operators, requiring all passengers to wear life jackets while boarding and throughout their trips.
Boat captains and crew members have also been instructed to provide safety briefings, explain the use of life jackets and emergency equipment, and ensure vessels are fully equipped with rescue and firefighting gear.
An inter-agency task force has been established to inspect businesses providing water-based tourism and recreational services.
The task force includes representatives from police, border guards and local authorities and will review compliance with safety regulations and recommend improvements.
The move follows a collision between two passenger vessels near Van Boi Beach in Lan Ha Bay on the morning of June 14.
According to authorities, a wooden tourist boat carrying 10 passengers was struck from behind by a larger steel-hulled tourist vessel and subsequently sank.
All passengers and crew members were rescued by nearby boats. However, a 43-year-old woman later died after being taken to hospital for treatment.
