N.J. Stat. § 54:1-20

If it shall appear that the value of any property contained in a taxing district or county, including railroad and canal property bearing the common burden, is relatively less than the value of other property contributing by taxation to a common burden, or that real or personal property which should be assessed therefor has been omitted from assessment, the commissioner may, after giving the notice required by sections 54:1-22 and 54:1-23 of this title, for the purpose of fixing or adjusting the proportion or quota of taxes to be levied as aforesaid, after a comparison of the values, or a like examination as to any omissions from the tax ratables, add thereto such sum or amount as shall seem equitable and to be warranted by the comparison and examination.