N.J. Stat. Ann. § 40:69A-42

The mayor shall designate the business administrator, any other department head, or the municipal clerk to act as mayor whenever the mayor shall be prevented by absence from the municipality, disability or other cause from attending to the duties of his office. During such time the person so designated by the mayor shall possess all the rights, powers, and duties of mayor. Whenever the mayor shall have been unable to attend to the duties of his office for a period of sixty consecutive days for any of the above stated reasons, an acting mayor shall be appointed by the council, who shall succeed to all the rights, powers and duties of the mayor or the then acting mayor.