N.J. Stat. Ann. § 43:13-22.52a

Any temporary employee included by this act in the definition of "employee" set forth in section one of P.L.1964, c. 275 (C. 43:13-22.50), shall, unless he is a member of another retirement system or otherwise ineligible, become a member of the retirement system established pursuant to P.L.1964, c. 275, as a condition of his employment; provided that he shall submit to and pass the physical and mental examinations required by the commission and shall provide such evidence of good health, at that time, as the commission shall require.