N.J. Stat. § 54:8A-52
If it shall appear to the satisfaction of the division, based upon an opinion of the Attorney General of this State, that any person whose wages, salaries or commissions are subject to deduction and withholding are liable for tax upon the same income under the law of the State of which he is a resident, under circumstances such as will entitle him to a reciprocity credit under this act sufficient to offset all taxes imposed hereunder, and that such State makes payment to the division of amounts deducted and withheld on account of earnings and gains derived by residents of this State from sources within such State and subject to tax under this act, the division may, by regulation, relieve residents of such State from being required to make any return under this act, and, upon the filing of such proofs as the regulations may require, relieve the employer of such taxpayers from the requirement to deduct and withhold any amount otherwise required by this act, for such period as the conditions herein stated continue to be satisfied; but the division may, notwithstanding the existence of such conditions, continue to require the making of such returns and the deduction and withholding of such amounts whenever it determines such action is appropriate or reasonably required to insure compliance with this act or whenever an appropriate official of such other State certifies that such State desires that such deduction and withholding be continued.
The division may consider amounts withheld under the provisions of this act as withheld for the benefit of the State of which such persons are resident but such amounts shall not be paid over to such State unless such State has complied with the provisions of this act and is thereby entitled to such amounts. Any amounts withheld, however, may be expended for any of the purposes specified in section 20 of this act.
N.J.S. § 54:8A-52