N.J. Stat. § 34:13A-60
The communications between a representative of a majority representative of employees and a unit member regarding the investigation and preparation for meetings and hearings of grievances and disciplinary disputes, shall be treated as confidential communications and shall not be subject to disclosure under the discovery rules of New Jersey administrative agencies, including, but not limited to, the Office of Administrative Law and the commission, or pursuant to section 17 of P.L. 2003, c. 95(C.2A:23B-17), and other applicable State laws authorizing arbitrators, presiding at labor arbitrations, to issue subpoenas. This section does not apply to the New Jersey Court Rules or to records that are required by statute, case law, or the New Jersey Court Rules to be made available to the public by entities provided for in Article VI of the New Jersey Constitution.
N.J.S. § 34:13A-60