The largest unionized group of Sonoma County government employees is set to begin voting on a new proposed contract Tuesday.

The agreement would cover about 1,700 workers represented by Service Employees International Union Local 1021. It also could set the framework for pending negotiations with the county's other 10 bargaining groups.

Details of the proposed three-year deal, which likely includes important pay, pension and medical benefit provisions, were unavailable Monday. County officials said they were not releasing any information to avoid interfering with the voting, which ends next Monday night.

If the union approves the contract, the county Board of Supervisors could do so as early as next Tuesday.

Union leaders said they plan to post the tentative agreement and an outline with key aspects of the proposal on their website at 5 p.m. Tuesday.

County officials said they were looking into how to provide the public an advance look at the deal without violating state labor laws.