Republican Charles D. Baker, seeking to distinguish himself from his rivals in the governor's race, urged state lawmakers yesterday to give cities and towns more flexibility to limit health care benefits for municipal employees without the approval of unions. Baker's proposal put him at odds with Governor Deval Patrick over an issue that is severely hampering Massachusetts communities and drawing heightened scrutiny from state and local leaders. Although Patrick has led efforts to overhaul the municipal health care system, he wants organized labor to continue to have a say in negotiations. The campaign of state Treasurer Timothy P. Cahill, who is running as an independent, said yesterday that creating jobs would remedy the situation but offered no specifics. Echoing a recent Boston Foundation study, Baker said that legislators should immediately change the law to allow local governments, without union negotiations, to join the state's larger, more flexible health care system and design their own health insurance plans. Such changes, which are opposed by public employee unions, could save taxpayers $100 million a year, he said. 'This plan will give local governments long-needed relief, and provides them the necessary tools to continue providing vital public safety services, and to spend tax dollars more efficiently,' Baker, a former chief executive of Harvard Pilgrim Health Care, said in a statement. If the Legislature declines to make it easier for communities to join the state Group Insurance Commission or design their own plans, Baker said, he would support a ballot initiative recently launched by a group of Massachusetts mayors, including Mayor Thomas M. Menino of Boston, that would take the issue directly to voters in 2012. In response to Baker's statement, Patrick's reelection campaign promptly noted that it was he who signed the 2007 law that allowed cities and towns to join Group Insurance Commission, the insurance pool that covers state employees. The switch requires approval by at least 70 percent of municipal union members, an obstacle that many cities and towns have been unable to overcome. Patrick, a Democrat, has filed a bill that would make it easier for communities to join the pool by lowering the threshold for union support to 50 percent. 'The governor strongly believes that our workers must have a seat at the table in health care negotiations,' his campaign spokesman, Alex Goldstein, said in a statement, going on to blame Baker for premium increases on 'working families' during his tenure at Harvard Pilgrim. 'His attempt to keep their voice out of this discussion is not surprising.' Cahill's campaign declined to specify his position on municipal health care but issued a statement. 'Real health care reform starts with creating jobs and fixing our economy, not the same plans from the same people who have benefited at the expense of the Massachusetts middle class,' the statement said. The competing statements signaled that the cost of municipal health insurance to taxpayers, highlighted by the Boston Foundation and in a recent Globe series, will emerge as a significant issue in the governor's race this year. It is hardly clear, though, whether lawmakers will act on changes to the system. Legislative leaders have been reluctant to strip local unions of bargaining rights. Health care costs added more than $1 billion to municipal budgets from 2001 to 2008, with many communities providing unusually generous benefits to employees, retirees, and elected officials, the Globe reported last month. Some cities now devote almost 20 percent of their budgets to health care. On March 3, the Boston Foundation released a study that concluded that cities and towns would save tens of millions of dollars in health care costs by joining the Group Insurance Commission. Boston, for instance, could reduce its health insurance premiums this fiscal year by up to 17 percent, or $45 million, said the report. Melrose, which joined the Group Insurance Commission in July, will probably save $1.6 million to $1.8 million annually, according to the report. Many unions across the state have balked at such a move because in many cases it would cost their members more, particularly in the form of higher copayments. Baker's running mate, Senate minority leader Richard R. Tisei, said in a phone interview yesterday that the fact that only 19 cities and towns have joined the Group Insurance Commission even though it would save taxpayers millions of dollars 'pretty much tells you all you need to know' about the power of municipal unions to hold on to current benefits. Tisei voted for the bill in 2007 allowing communities to join the commission with union approval; he said yesterday he felt it was the best measure the Legislature would approve at the time. In a recent interview, Brad Tenney, secretary-treasurer of the Professional Fire Fighters of Massachusetts, an umbrella group of local unions, said his members were willing to negotiate on health care benefits. But he said it was 'unfair to look at health insurance in a vacuum,' adding that union members have given up pay raises or taken smaller ones to preserve those benefits. Blue Cross Blue Shield of Massachusetts, which provides health insurance to municipal workers in most cities and towns under the current system, said in a statement yesterday that some communities may pay more if they joined the Group Insurance Commission. 