N.J. Stat. § 19:49-3
At least one week prior to the start of the early voting period for any primary, local, or general election two sets of official ballots shall be provided for each voting machine, for each polling place, for each election district, for use in and upon the voting machine. One set thereof shall be inserted or placed in or upon the voting machine and the other shall be retained in the custody and possession of the county board of elections or the superintendent of elections or the municipal clerk, as the case may be, having custody of voting machines, unless it shall become necessary during the course of the election to make use of the same upon or in the voting machine. At the close of the election all official ballots, except those actually in or upon the voting machine at the close of the election, whether the same shall have been used in the machine or not, shall be returned to the official providing the same in the manner by this Title provided.
N.J.S. § 19:49-3