The Xeni Gwet'in want the confidential session as they discuss identification of ancestral graves around the proposed New Prosperity Gold-Copper Mine, 125 kilometres southwest of Williams Lake.
The review panel holds hearings on the road this week, as it travels to First Nations communities around the huge mine, proposed by Taseko Mines Ltd.
Critics fear the $1 billion mine will destroy culturally significant Fish Lake and they doubt Taseko's claim that the plan has been revised and the lake will be spared.
Although the New Prosperity mine has twice failed to pass the federal environmental assessment process, the B.C. government approved it in 2010, finding that economic benefits outweigh environmental considerations.
Taseko says the project will create about 700 direct jobs and produce $10 billion in revenue for the federal and provincial governments over its 20-year lifetime.
The review panel is expected to decide by late Wednesday whether to hold private hearings with the Xeni Gwet'in.