The breach, in Tan Nhuan Dong Commune of Chau Thanh District, is 100 meters long and four meters into the river bank.

"I heard a loud rumbling and the sound of the earth being torn apart in the middle of the night," a local said.

"When everyone ran out to check, the houses were already under water."

No one was injured, Dang Minh Dong, chairman of the commune People’s Committee, said.

After authorities discovered signs of erosion a few days earlier, they already advised people not to stay in their houses on Sunday night, he added.

Authorities are trying to salvage the wreckage and recover lost properties from under the river. Temporary shelters have been arranged for people who lost their homes, and six other households in the vicinity, also threatened by the breach, have been evacuated.

Land erosion has become a frequent occurrence in many coastal and riverine provinces in Vietnam, claiming hundreds of houses in the last decade.

It has become a particularly acute problem in the Mekong Delta, Vietnam's food basket which grows half of its rice and accounts for 90 percent of its rice exports.

The delta is losing 500 hectares of land to sea and river erosion every year, according to the Ministry of Agriculture and Rural Development.

It is estimated that by 2050 the lives of one million people will be directly affected by this.

The Ministry of Construction last year submitted a proposal to build concrete barriers to protect 44,800 families.