Any referee, who is a counselor at law duly admitted to practice by the supreme court, and who has served as a referee in the bureau for not less than two years, may at the discretion of the commissioner be certified to the civil service commission as eligible for examination for the position of deputy commissioner of compensation, and upon successfully passing the examination, he may be advanced to said office, as a member of the workmen’s compensation board in addition to the deputy commissioners appointed under section 34:1-57 of this title.