N.J. Stat. § 40:64-2
The first commissioners shall be appointed within 60 days after the ordinance providing for the commission shall become effective, and their terms of office shall commence upon the day of their appointment and be for the respective periods of one, two, three, four and five years, if the commission consists of five members, beginning on January 1 next succeeding such appointment. If the commission is to consist of six members, the first commissioners shall be appointed as above, except that two shall be appointed for five years; and if the commission is to consist of seven members, two shall be appointed for five years and two shall be appointed for four years. In the event that the membership of any commission is increased, the new members shall be appointed in such manner that the terms shall expire in accordance with the foregoing. The terms of each appointee shall be designated in his appointment. All subsequent appointments, except to fill vacancies, shall be for the full term of five years, to take effect on January 1.
If the ordinance providing for alternate members provides for two alternate members, they shall be designated at the time of appointment as "Alternate No. 1" and "Alternate No. 2" and shall serve during the absence or disqualification of any regular member or members. The term of each alternate member shall be five years commencing on January 1 of the year of appointment; provided, however, that in the event two alternate members are appointed the initial term of "Alternate No. 2" shall be four years and the initial term of "Alternate No. 1" shall be five years. The terms of the first alternate members appointed pursuant to this section shall commence on the day of their appointment and shall expire on the fourth or fifth December 31 next ensuing after the date of their appointments, as the case may be. An alternate member may participate in discussions of the proceedings but may not vote except in the absence or disqualification of a regular member. A vote shall not be delayed in order that a regular member may vote instead of an alternate member.
N.J.S. § 40:64-2