Any municipality may, by ordinance, establish an urban rehabilitation program and may authorize any existing board, commission, department or agency to be the urban rehabilitation agency or may, by ordinance, establish a new board, commission, department or agency to act as the urban rehabilitation agency. Such new urban rehabilitation agency shall be composed of not less than three nor more than nine members, all of whom shall be residents of the municipality appointed by the chief elected official with the approval of the legislative body. Those first appointed shall be designated to serve one, two and three years respectively and thereafter members shall be appointed annually to serve for three years. Each member shall serve until his successor is appointed and has qualified. Action by such an urban rehabilitation agency shall be taken by majority vote of members present, provided no action may be taken unless at least fifty per cent of the members are present. An urban rehabilitation agency created pursuant to this section shall select a secretary, who may be a member of the agency and may elect or employ such other officer, agent, technical consultants, legal counsel and employees as the agency requires. The members shall serve without compensation but may be reimbursed for necessary expenses incurred in the performance of their official duties.