When an examination of the books, records, papers, vouchers or accounts of a taxpayer is conducted on the premises of an agent of the taxpayer by the Director of the Division of Taxation or by any employee thereof, the taxpayer shall provide such agent evidence in writing that the agent is authorized to act in behalf of the taxpayer in making any application, deposition, statement, or report required by the director in the administration of any tax law, and the agent shall produce such authorization to the representative of the Division of Taxation.
N.J.S. § 54:50-2.1