N.J. Stat. § 40:41A-118
The district commissioners shall consist of four members, two to be appointed by the chairman of the county committee of each of the two political parties whose candidates for Governor receive the largest number of votes at the most recent gubernatorial election. Each county chairman, in making such appointments, shall give due consideration to the representation of the various geographical areas of the county. Appointments of district commissioners shall be made on or before the third day following the election at which the voters of the county shall have adopted a district representation system and commissioners shall serve until they discharge their duties under sections 119 through 122 of P.L. 1972, c.154 (C.40:41A-119 through 122). With respect to section 123 of P.L. 1972, c.154 (C.40:41A-123), appointments shall be made on or before the tenth day following the receipt by the Governor of the official decennial census of the United States for New Jersey, and commissioners shall serve until they discharge their duties under that section. If the commissioners fail to certify district boundaries, pursuant to sections 119 through 123 of P.L. 1972, c.152 (C.40:41A-119 through 123), on or before the date fixed or if prior thereto they determine that they will be unable to do so, they shall so certify to the Chief Justice of the Supreme Court of New Jersey, who shall appoint as a fifth commissioner a fair-minded and impartial person who shall not have held elected public or party office in this State at any time during the three-year period immediately prior to appointment as a commissioner. The commissioners, by a majority of the whole number thereof, shall within one month after the appointment of such fifth member certify district boundaries.
N.J.S. § 40:41A-118