N.J. Stat. Ann. § 54:4-55.1

At any time after the tax lists and duplicates shall have been delivered to the county board of taxation as provided in R.S. 54:4-35, the county board of taxation may, for such time and upon such terms and conditions as it deems proper, permit the collectors of the various taxing districts in the county to have custody of the duplicates. No collector shall make any change or alteration in assessments in the duplicate while it is in his possession. Every collector who shall fail to return the duplicates to the county board of taxation in accordance with the terms and conditions of its delivery or upon its demand shall be subject to a penalty of $10.00, and to an additional penalty of $10.00 for each additional day such failure shall continue. The penalties shall be collected by civil action against the collector at the instance of the county board of taxation, in any court of competent jurisdiction and the amount of the penalties when collected shall be paid into the county treasury.