The future of the 11 GW Belo Monte Dam on Brazil’s Xingu River has been put in doubt after a judge ordered work on the project to stop.

Judge Carlos Castro Martins ruled in favour of a fisheries group and has barred any work that would interfere with the natural flow of the Xingu.

The fisheries group had argued that the dam would affect local fish stocks and harm indigenous people who make a living from fishing.

The Belo Monte dam is an important element of Brazil’s Accelerated Growth Programme (PAC) and will be the third largest hydropower plant in the world when complete. It is being developed by a consortium led by Brazilian energy group Chesf, which earlier this year awarded major supply contracts to Alstom, Andritz and Voith.

The Norte Energia consortium is expected to appeal the decision. It said in a statement that it is committed to socio-economic development in the Xingu region and is investing R$3.7 billion in social and environmental projects.