N.J. Stat. § 54:4-9.3
Except in the case of a willfully false or fraudulent return made with intent to evade valuation, assessment or taxation of personal property pursuant to chapter 4 of Title 54 of the Revised Statutes, no increase in any taxable valuation of property reported or required to be reported in such return shall be made by the assessor after the expiration of 2 years from the date of the filing of a return; provided that where no return required by law has been filed, the taxable value may be determined and assessed at any time within 6 years after the date upon which such return was required to be filed. Notwithstanding any other provision of law relating to the assessment of taxable property omitted from assessment under said chapter, the times within which such assessments of tangible personal property may be made shall be as provided in this section.
N.J.S. § 54:4-9.3