The ruling follows legal action recently filed by environmental groups who argue that the project was approved by the country’s government without taking into account technical reviews. The project has now been temporarily halted until the project is re-evaluated, which could take several months, local media reported.

The $3.2B HidroAyse project – to be developed by Chile’s Endesa and the Spanish firm Colbun SA – will involve the construction of five plants on two rivers, two on the Baker river and three on the Pascua river, with annual average electricity production of 18,430GWh. All five schemes would require reservoirs to be built.

In May this year, the Aysén Environmental Review Commission approved the scheme following a three-year environmental review.

The project is seen by Chile’s government as key to satisfying the country’s growing energy needs. Environmental groups have however claimed the project will endanger pristine forests and destroy wilderness areas of Patagonia.