Whenever the department or office has reason to believe that any person, entity, or health maintenance organization has engaged, or is engaging, in this state in any unfair method of competition or any unfair or deceptive act or practice as defined in s. 641.3903 or is operating a health maintenance organization without a certificate of authority as required by this part and that a proceeding by it in respect thereto would be to the interest of the public, the department or office shall conduct or cause to have conducted a hearing.