Ecojustice says it's seeking a Federal Court order to declare it was illegal for the company Marine Harvest to move the salmon to an open-pen fish farm in Shelter Bay last month.
The group's lawyer Margot Venton says the federal Fisheries Department is standing by while a private company puts disease-carrying fish into the ocean.
Ecojustice is taking the legal action on behalf of marine researcher Alexandra Morton, who alleges the Atlantic salmon were infected with a virus called PRV, which may cause a disease that affects the muscles and heart of salmon.
Ecojustice says the disease is thought to have spread to virtually all fish farms in Norway.
Morton says fisheries officials should have responded to the discovery of the virus in B.C. with measures to protect wild salmon, but instead they have given Marine Harvest permission to expose B.C.'s wild salmon to this disease.