The remaining sites could contain toxic waste like batteries and expired/discarded medicines, which leach into and contaminate groundwater, Dung said at an international conference on water management and waste treatment in Saigon this week.

There are 200 incinerators in the country to burn trash, but most could only handle 5-10 tons a day, he said.

Vietnam's 830 cities discharge around 38,500 tons of solid waste daily or around 14 million tons a year, but only 75-80 percent of it is collected since it is done manually or semi-mechanically and technologies and policies to support the collection process are inadequate, he said.

People's failure to sort their trash poses further difficulties in sorting and collection, he added.

With 280,000 tons a year, Vietnam is among the world’s top four generators of plastic waste, according to a World Bank report.

Over 70 percent of this is buried, leading to loss of land area and pollution.

Several burial sites in major cities like Hanoi, HCMC or Da Nang are overloaded and affect people’s lives. Hanoi and HCMC each spend VND1.2-1.5 trillion ($52-65 million) a year, or around 3.5 percent of their budget, on collecting and treating waste.

At a conference in July, Nguyen Thuong Hien, head of the Vietnam Environment Administration's waste management department, had said there was no solid-waste treatment model in the country that met all technical, economic, social, and environmental requirements.