MERRIMACK — Six months after their contract expired, a tentative agreement has been reached between the town and the New England Police Benevolent Association Local 12.

“As you know, all of our local unions except for Teamsters are out of contract,” Town Manager Eileen Cabanel told the town council on Thursday. “We’ve been in negotiations with each one of them.”

The board unanimously agreed to ratify the contract for about 30 police employees, effective July 1, 2011, to June 30, 2013. Although there was no wage adjustment for last year, a 1 percent wage adjustment was approved for all members for 2012-13.

In addition, there was an increase to employee office and prescription co-pays, with office visits increasing from $5 to $10, and pharmacy and mail order pharmacy costs also increasing, according to Cabanel.

Following months of negotiations, the new contract will save the town $21,615, with a net cost to the town of $31,916, she said.

“This turns out to be a fairly good deal,” said Councilor Tom Koenig, adding there is always give and take in negotiating new contracts. Although it does not address all of the town’s concerns, Koenig said it does help save some money for health costs.

Councilor Dan Dwyer agreed the health insurance concessions were important, but stressed the issue of merit pay should be considered in future negotiation sessions.

A former town councilor, Tim Tenhave, urged the council to study further a potential merit system for all town contracts.

“I have great respect for these folks, but merit systems reward performance, they don’t reward mediocrity,” said Tenhave.