N.J. Stat. § 34:13A-18
The arbitrator shall not issue any finding, opinion or order regarding the issue of whether or not a public employer shall remain as a participant in the New Jersey State Health Benefits Program or any governmental retirement system or pension fund, or statutory retirement or pension plan; nor, in the case of a participating public employer, shall the arbitrator issue any finding, opinion or order regarding any aspect of the rights, duties, obligations in or associated with the New Jersey State Health Benefits Program or any governmental retirement system or pension fund, or statutory retirement or pension plan; nor shall the arbitrator issue any finding, opinion or order reducing, eliminating or otherwise modifying retiree benefits which exist as a result of a negotiated agreement, ordinance or resolution because of the enactment of legislation providing such benefits for those who do not already receive them.
N.J.S. § 34:13A-18