A panel in Arizona, where voters once turned down a constitutional ban on gay marriage, approved a plan Tuesday to provide taxpayer-subsidized health coverage for the domestic partners of state employees and retirees.

The Governor’s Regulatory Review Council, which has the final say over many agencies’ proposed rules, voted 4-0 to approve changes floated by the Department of Administration with support from Gov. Janet Napolitano, a Democrat. Some Republican legislators opposed the move.

Dependents of domestic partners also will qualify. Employees will be able to sign up for benefits as of Oct 1.

Supporters said providing benefits to partners and their dependents would help the state reduce costly turnover by being more competitive in recruitment and retention. Napolitano, among others, has argued that it was a question of fairness.

In her first year in office, Napolitano issued an executive order banning discrimination in state personnel practices based on sexual orientation.

Critics said the benefits rule changes would undermine the institution of marriage, burden the state with added costs at a time of budget trouble and, by doing it through rule changes, trample the Legislature’s policymaking role.

The state Senate last month narrowly rejected a Republican measure to block the move by changing state law to define “dependent” as a spouse or unmarried child of an employee or retiree.

There are about 65,000 state employees and 9,000 state retirees in Arizona. According to state estimates, the number of partners likely to be covered ranges from 317 to 853.

Arizona voters made their state in 2006 the only one that year to defeat a constitutional amendment to ban same-sex marriage. At least 15 other states already provide domestic partner benefits.