CONCORD, N.H. – Gov. John Lynch announced Friday that the state had reached tentative agreements with negotiators for three labor unions on contracts that will save the state nearly $50 million and avert the need to lay off potentially 500 workers in September.

Lynch announced the accords in joint statements with the State Employees’ Association, which represents most of the state’s 11,000 workers, and with the New Hampshire Troopers Association and New England Police Benevolent Association.

Lynch said he was pleased the deals could be reached to avoid widespread layoffs.

The unions agreed to money-saving health benefit and personnel-related changes.

The state budget required Lynch to save $50 million in personnel costs, with $20 million coming from state-funded accounts, and to implement the savings by Sept. 1. Otherwise, the governor has to cut labor costs by Dec. 1.

The unions must vote on the two-year contracts before they can take effect.

“This agreement makes real progress in addressing the rising cost of health care, which is a benefit to our taxpayers and our employees,” Lynch said of the agreement with the SEA.

Earlier this month, Lynch told state agency heads to develop contingency plans to lay off potentially hundreds of state workers if negotiations failed. The agencies have until Aug. 8 to submit plans to be implemented around Sept. 8. Lynch spokesman Colin Manning said the state must continue preparing for layoffs should the unions not ratify the agreements.

SEA President Diana Lacey said preparations for a contract vote and layoffs have to follow simultaneous tracks given the legislative mandate.

“I don’t fault him for that,” she said of Lynch continuing his contingency effort.

The SEA will present the proposed agreement to its bargaining Senate, a leadership group, on Aug. 8 and recommend acceptance. If the Senate recommends ratifying the contract, ballots would be mailed by mid-August, Lacey said. Union members would have two weeks to vote and ballots would be counted in early September.

The layoffs would have been in addition to an as-yet unknown total of layoffs from budget cuts.

The governor’s office said so far it knows of about 130 executive branch layoffs from budget cuts, but more are likely as agencies comply with cuts whose amounts were specified, but not the programs to be cut.

Lynch made it clear in his February budget address that he wanted the next contract with workers to include changes in health benefits to save money.

Lacey said the Republican-controlled Legislature overrode longstanding personnel rules in the budget package to limit workers’ rights when it eliminated 1,100 vacant positions and laid off workers. She said the union wanted those protections added to the contract.

The announcement from the governor’s office did not spell out the details of the agreement but said it restores modified bumping rights, which allow more senior employees who are laid off to take the jobs of less senior workers.