N.J. Admin. Code § 19:14-5.1
A motion for leave to intervene shall be filed in writing or made orally on the record at hearing. A motion shall state the grounds for intervention and the extent to which intervention is sought. Any party opposing a written motion to intervene may file a written response within five days, together with proof of service on the other parties. If the motion is made orally at hearing, any party opposing intervention may do so orally on the record. Filing, service, and proof of service of a motion and any response shall conform to the provisions of 19:14-4.3. The Commission, the Director of Unfair Practices, or the hearing examiner, as the case may be, may by order permit intervention on such terms as may be deemed just.
N.J. Admin. Code § 19:14-5.1
See: 27 New Jersey Register 2555(a), 27 New Jersey Register 3387(a).