Entire villages have been swept away and 6,600 people are homeless after a hydropwer dam built by South Korea's SK Engineering and Construction and Laos and Thai partners collapsed.

South Korean company, SK Engineering and Construction said today that it has formed a crisis management team to respond to a deadly flood in Laos that affected a dam it built in the country.

The company said its President Ahn Jae Hyun and senior company officials have left for Laos to figure out the scope of the damage caused by the flood, which occurred late yesterday, and to support rescue operations there, Yonhap reports.

The Associated Press cited the official Lao news agency KPL said the Xepian-Xe Nam Noy hydropower dam in Attapeu province collapsed Monday evening, releasing large amounts of water that swept away houses and made more than 6,600 people homeless.

The builder said huge amounts of water flooded over the Xepian-Xe Nam Noy hydropower plant dam in San Sai district of Attapeu province in the southeast of the country, sweeping away nearby villages and displacing around 6,600 people. Hundreds of people are reported missing.

Although initial media reports said one of the dams under construction collapsed, the company said it is checking whether the dam actually failed or if water swept over it.

An official from the company said the area had been hit by heavy rainfall three times greater than normal.

"The overflow of water went downstream, which had already been flooded, causing more damage," he said.

The company is supporting the Laotian government's rescue operations by bringing in helicopters from Thailand to help rescue stranded people. Villagers in nearby areas have been evacuated, the company said, adding that the affected area is surrounded by dense forest where communication isn't easy, complicating rescue efforts.

The dam was built by a joint venture comprising SK E&C and Laos and Thai partners beginning in 2013 and was expected to go into full operation next year.-Photo: Lao News Agency