N.J. Stat. § 43:15A-137
Notwithstanding any other law regarding the purchase of service credit in the retirement system, a member of the Legislature may purchase credit for all previous legislative service by paying into the annuity savings fund 5%, and 5.5% after July 1, 2007, of the salaries he received in such prior periods, in which event he shall agree to make such purchase within 1 year after the effective date of this supplementary act or during the first year of membership as a member of the Legislature; if the request for the purchase is received beyond the 1-year period, interest shall be added to the amount of the arrearage obligation at the regular interest rate. The purchase of such credit may be by lump sum or in regular installments over a maximum period of 10 years.
In the case of any member of the Legislature coming under the provisions of this section, full pension credit for the period of service for which arrears are being paid by the member shall be given upon the payment of at least 1/2 of the total arrearage obligation and the completion of 1 year of membership and the making of such arrears payments, except that in the case of retirement pursuant to P.L. 1954, c.84, sections 38, 41(b), 48 and 61 and to the provisions of this supplementary act, the total membership credit for such service shall be in direct proportion as the amount paid bears to the total amount of the arrearage obligation of the member.
The contributions of all members of the Legislature related to their legislative service shall be adjusted for all years prior to the effective date of this supplementary act to determine either an overpayment or shortage in the separate account, requiring the payment of contributions at the percentage of salary provided for in this section. Overpayments shall be refunded and shortages shall be established as arrearage obligations to be satisfied in the same manner as any other arrearage obligation established pursuant to this section.
No member shall receive credit for any legislative service for which he has not contributed as required by this section.
N.J.S. § 43:15A-137