The State may establish a deferred compensation retirement plan in accordance with sections 457 and 3121 of the Internal Revenue Code of 1986, as amended, for the benefit of employees to defer a portion of their compensation to a future period of time. Participation in the plan shall be mandatory, with a mandatory payroll deduction by the employee equal to seven and five-tenths per cent of the employee's gross monthly wages, which shall be contributed to the plan. A county may enter into a formal agreement with the State to extend the State's plan and its provisions to part-time, temporary, and seasonal or casual employees of the county; provided that:
HRS § 88F-2