A controversial benefit will remain in place for about 465 top Sonoma County government officials until the end of this year, the Board of Supervisors decided Tuesday.

The move on deferred compensation retirement accounts came despite heated opposition from rank-and-file workers in the county's largest union, which denounced the perk's inclusion last month in a compensation package for administrative managers, department heads and county supervisors.

The mostly executive-level benefit has long been a target of unions and is set to end for all other county workers. It was partially extended for top officials because of a legal conflict with granting those employees an offset through health reimbursement accounts.

Members of Service Employees International Union Local 1021 wanted it removed immediately. But even with the perk, top officials are still set to take greater cuts in compensation, starting at 5.1 percent and topping out at 8.5 for county supervisors. Pay and benefit concessions for SEIU members total 2.25 percent.

The benefit no longer factors in pension calculations and county administrators said Tuesday they were unable to find any other suitable offset after being directed to do so last month by the board.