N.J. Stat. § 54:29A-63
For the purpose of administering this act, the commissioner, whenever he deems it expedient, may make or cause to be made by an employee of the State Tax Department, engaged in the administration of this act, an audit, examination, or investigation of the books, records, papers, vouchers, accounts, and documents of any taxpayer, and also field surveys, inspections and examinations of all lands and physical property. It shall be the duty of every taxpayer and of every director, officer, agent or employee of every taxpayer to exhibit to the commissioner or to any such employee of the State Tax Department all such books, records, papers, vouchers, accounts, and documents of the taxpayer and to facilitate any such audit, examination, field examination or investigation so far as it may be in its or their power so to do. It shall be lawful for the commissioner, or any employee in the State Tax Department by him thereunto designated to take the oath of any person signing any application, deposition, statement, or report required by the commissioner in the administration of this act. If any returns are not made, the commissioner shall ascertain the necessary facts from the best information he can obtain and in such manner as he may find convenient, using his personal knowledge and judgment.
N.J.S. § 54:29A-63