A new labor contract agreed to this week between Nassau County Executive Edward Mangano and leaders of the county's correction officers union will cost $17 million over the next four years, administration officials said Friday.

The agreement with the Correction Officers Benevolent Association would provide a series of pay hikes for the union's 900 members that with compounding total more than 13 percent through 2017.

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The agreement, which must be approved by union members, the county legislature and the Nassau Interim Finance Authority ends a wage freeze in effect since March 2011.

The new contract provides an immediate 3.5 percent pay hike, followed by a 3.75 percent raise in 2015, a 3.5 percent hike in 2016 and a 2 percent increase in 2017. Some members also would get step increases.

Like the four other Nassau unions that signed new labor deals with the county last month, COBA agreed to give up an annual pay raise that had been due in 2013 as well as one year of step increases. New union members would also have to pay 15 percent toward their health insurance premiums or choose a less costly plan and not contribute.