Superior Court Associate Justice Sarah Taft-Carter said Tuesday she had met with the parties and they agreed to try mediation.
Unions and retirees want to overturn the 2011 pension law, which raised retirement ages and suspended pension increases. They say the changes are unconstitutional and unfair.
State leaders including Treasurer Gina Raimondo say the changes were necessary to keep pension costs from crippling state finances. Raimondo had opposed negotiations but says the state will participate "in good faith."
The parties have been referred to the Federal Mediation and Conciliation Service in Washington, D.C. The judge will be updated on mediation efforts on Feb. 1.