A major hospitality operator has accused senior Fair Work Commission members of bias after they raised extraordinary concerns that the company may have lied about an agreement that allows staff to opt out of all penalty rates.

Mantle Group asked a full bench of the commission to recuse itself on grounds of apprehended bias during what was intended to be a short hearing on Friday to respond to the bench’s concerns that the few “employees” who voted on the company’s controversial deal were in human resources.