The Nunatsiavut (noon-AHT'-see-ah-voot) Government and the NunatuKavut (noon-ah-TWO'-ha-voot) Community Council have filed requests for judicial review in Halifax.
They're asking the Federal Court to revisit a decision by the Department of Fisheries and Oceans to grant permission to begin work on a dam without properly consulting them.
Nunatsiavut president Sarah Leo says the project will damage recognized Inuit lands and cause potential health issues.
She says such concerns were recognized by a federal-provincial environmental assessment panel but have not been accommodated.
NunatuKavut president Todd Russell, whose group has no federally recognized land claim, says the province has failed to adequately consult his members.
The authorization to start building the dam was granted to provincial Crown corporation Nalcor Energy, which declined comment as it reviews the court applications.
No one from the Department of Fisheries and Oceans or Natural Resources Canada could be immediately reached for comment.