N.J. Stat. § 19:7-6.1
Unless express permission be given by the district board, not more than one challenger appointed for a party, candidate, or on a public question, shall be present at any one time in any polling place while serving and exercising the powers of a challenger and during the hours when the polls are open for voting. If the district board shall in any case give permission for more than one challenger so appointed to be present at any one time in any polling place, it shall on the same grounds and on request permit a like number to be present on behalf of any opposing party, or on behalf of any other candidate for the same office, or on the other side of any public question.
The provisions of this section shall not apply to any challengers appointed by the chairman of a county committee, pursuant to paragraph 2 of subsection b. of R.S. 19:7-1, except that no more than one such challenger shall be present at any time in a polling place while serving and exercising his or her power as a challenger during the hours when the polling place is open for voting.
N.J.S. § 19:7-6.1