Telephone numbers that often sent spam messages should be blocked, experts agreed at a recent conference held by the Hanoi Department of Information and Communications.

MobiFone Deputy Director Nguyen Dinh Chien said the company has implemented several measures to block spam messages, but they would not have a system blocking messages based on keywords until March.

On the MobiFone network, telephone numbers beginning with 1900 – which often sent spam messages – were virtually all under control, said Chien. The most pressing problem was spam messages inviting clients to buy real estate, which the company had not yet found an effective way to tackle.

Since the beginning of 2014, MobiFone has blocked more than one million subscribers.

Doan Xuan Hop, deputy head of VinaPhone's sales office, said that the company also implemented various measures to manage spam messages. Besides improving management of pre-paid subscribers' registration, VinaPhone would assign workers to be on duty 24/7 to supervise subscribers sending large amounts of messages.

Last year, VinaPhone blocked nearly 700,000 telephone numbers and 79 numbers beginning with 1900 for sending spam messages.

Hop added that VinaPhone has joined hands with the Vietnam Computer Emergency Response Teams (VNCERT) to control spam messages. If VinaPhone discovered violations, the company would temporarily disconnect the violators from the network or cancel their registration.

Deputy Director of the Telecommunications Department of the Ministry of Information and Communications Nguyen Xuan Tru said that companies should set up detailed plans to address the issue and co-ordinate with each other to manage spam messages.

Tru added that the Hanoi Department of Information and Communications should tell the municipal People's Committee to promulgate regulations related to the issue such as setting up a hotline to receive complaints about spam messages.

VNA