A regional or area agreement or any modification, extension or amendment thereof shall not become effective unless:
(a) The commissioner finds that such agreement will serve the general public interest and will not substantially duplicate the services of any existing agreement and approves the provisions thereof;
(b) The Attorney General certifies that the agreement complies with the laws and public policy of New Jersey and with the provisions of this act; and
(c) A copy of the agreement or any modification, extension or amendment thereof is filed with the clerk of the governing body of each participating local unit.