N.L.'s Crown-owned Nalcor Energy and N.S.'s Emera Inc. agreed in November on a $6.2 billion plan to generate 824 megawatts of power at Muskrat Falls on Labrador's Churchill River.
According to the deal, electricity will be moved first to Newfoundland with much of it later relayed through Nova Scotia by underwater cables.
The provinces have asked the federal government for a loan guarantee to help with the project, which was before a Senate energy committee hearing in Halifax earlier.
"This project is of significant importance to our province, to our economic future and to a sustainable future for the project as a whole," said Gilbert Bennett, the vice-president in charge of the project.
NunatuKavut, the group formerly known as the Labrador Metis Nation, filed an injunction to stop the hearings from beginning.
Members of NunatuKavut said the hearings must be stopped because the Newfoundland and Labrador owned energy company, Nalcor, hasn't consulted them about the proposed development.
And some groups see few long-term benefits for people living in the area and are worried about the huge project's environmental impact.
Clarice Blake Rudkowski, a member of environmental group Grand Riverkeeper, is calling on the panel to block the project.
"We'll dance for glee if they did, but if not, how do we minimize the impact that's the big issue?" she said.
Former premier Roger Grimes also called on the people of Newfoundland and Labrador to weigh carefully the consequences of the project slated for Labrador's Muskrat Falls. Grimes said people are not asking enough questions about the $6.2 billion deal.