The pollution has mostly been caused by untreated wastewater discharged by households, industrial zones, hospitals, and craft village.

"We now have several regulations scattered over several legal documents," said Pham Van Loi, head of the Institute of Science for Environmental Management.

This has meant that efforts to control water pollution throughout the country have not been effective, Loi said.

Many localities hardly implement existing regulations on controlling water pollution, he added.

He said concerned agencies should learn from the experiences of other countries before issuing effective regulations for managing water pollution in Vietnam.

Loi also suggested the agencies to learn experiences from foreign countries before issuing the set of rules on controlling water pollution.

Vietnam is home to more than 2,300 rivers.

Le Hoang Anh, deputy head of the Centre for Environmental Monitoring said that surface water in rivers in the northern region was highly polluted.

She cited the Nhue and To Lich rivers as examples.

The pollution has mostly been caused by untreated wastewater discharged by households, industrial zones, hospitals, and craft village, she said, adding the situation was almost the same in the southern region.

For instance, wastewater discharged from industrial zones had polluted long stretches of the Dong Nai River, Anh said.

In the Cuu Long (Mekong) Delta, wastewater from aquaculture and agricultural production had polluted local rivers, she added.

Anh suggested that authorised agencies in the northern region step up installation and operation of wastewater treatment systems for handling household waste in major cities like Hanoi and Hai Phong, as well as provinces like Quang Ninh.

In the southern region, there is a need for greater focus on treating wastewater discharged by industrial zones, she said.

Mekong Delta authorities, meanwhile, should increase inspections of aquaculture farms as well as agricultural production processes that generate polluting waste, she added.

Loi said authorized agencies should be asked to ratify and apply international conventions on water pollution.