The dam will be the first to be built on the Lower Mekong basin, and countries that share this river – Cambodia, Laos, Thailand and Vietnam – have an agreement that any such development would be decided through their joint body, the Mekong River Commission (MRC).
In April Laos agreed to suspend work on the dam in the face of concerns from the three other MRC members and environmental groups.
The key concern was that the environmental assessment for the project was inadequate, meaning that the potential impacts of the project had not been understood and explored.
According to environmental group International Rivers, the livelihoods of 60 million people in the lower Mekong region are at risk if the dam goes ahead without a proper assessment.
Concerns are held about the impact on fish stocks, due to disrupted breeding and migratory patterns, and the impact on agricultural land, which relies on the nutrient-rich silt that is washed downstream by the river.
Following the April meeting, Laos had agreed to suspend work on the project until environment ministers of the four countries could meet to discuss it in October or November this year.
Laos has commissioned a study into the preparation and found it to be complete and therefore claims to be within its rights to push ahead with the project, having consulted adequately with the three other members of the MRC.
There has been no further study of the environmental impacts of the scheme.