More than 40 people went on trial in Vietnam Monday over illegal sand mining in the Mekong Delta, state media said, as concern mounts over the environmental impact of overexploitation.

A former senior provincial official who took a $300,000 bribe to allow mining in the area is among 44 people facing justice at the Ho Chi Minh City court, in the country's largest-ever illegal sand mining case, Lao Dong newspaper said.

Mining sand -- mainly for concrete used in construction -- has boomed in Vietnam in recent years, prompting dire warnings over the environmental consequences.

Nguyen Thanh Binh, the former chairman of the people's committee in An Giang province in the Mekong river delta, is accused of abuse of power, reported court newspaper Cong Ly.

He and other officials ordered subordinates to issue a sand mining licence to the Trung Hau 68 company even though it did not qualify, the report said.

The former CEO of the firm, Le Quang Binh, is accused of bribery, violation of regulations on exploration and exploitation of natural resources, and money laundering.

Between December 2021 and July 2023, the company sold over 3.7 million cubic metres of sand for around $11.5 million, according to Cong Ly.

In a 2023 report from conservation group WWF, experts warned that sand mining to feed Vietnam's construction boom was depleting resources so fast that the Mekong Delta -- the country's "rice bowl" -- could run out in just over a decade.

With less sand, river flows become lighter and faster, and hit the banks at greater speed, accelerating erosion.

Around 20,000 households need to be resettled because of the risks, according to Vietnam's natural disaster prevention and control department.

The WWF puts the figure much higher, saying half a million people could lose their homes.

A verdict in the Ho Chi Minh City trial is expected on April 4.

Nguyen Thanh Binh has already paid back $300,000 to the court, Cong Ly newspaper said.