Legislation filed earlier this year by Gov. Deval Patrick seeks to reform the health care payment system by shifting the state away from the traditional "fee-for-service" approach and toward so-called "global payments," which stress overall patient outcomes over the quantity of tests and procedures performed. While also intended to ultimately lower costs for consumers and small businesses, the governor's bill does not directly address the market clout issue that has been highlighted by state Attorney General Martha Coakley in two successive annual reports on health care costs.

Mariano indicated that his bill was not intended to compete with Patrick's plan, but instead help pave the way for payment reform measures that would take longer to implement.

"Changing the payment system will take several years but employers and consumers can't wait that long," the majority leader said in a statement. "If we expect the health care system to function properly and more efficiently, closing the gap between lower-paid providers and higher-cost providers needs to be a priority and we must start now."

Mariano estimated that the bill would immediately result in at least $267 million in health care savings.

Lynn Nicholas, president of the Massachusetts Hospital Association, said providers had already taken several positive steps toward controlling costs and she warned against government "micromanaging" price variations.

"Lowering existing payments to some hospitals could have some very serious unintended consequences," said Nicholas. Such hospitals could be forced to raise the price of their existing services or eliminate valuable but undercompensated services."

Instead of seeking a redistribution of funds between hospitals, government could help many financially troubled hospitals and help lower insurance premiums by paying an adequate share for Medicare, Medicaid and uncompensated care, Nicholas said.

Coakley's second annual report on health care costs, released in June, found that wide variations in payments made by health insurers to providers could not be explained by differences in the quality of care or the complexity of the services provided, but were instead rooted in the size and relative market leverage of different providers.

The report said a global payment system would not by itself correct these disparities, though Coakley also cautioned against aggressive government intervention that could stifle competition in the health care market.

Coakley did not immediately respond to a request for comment on Mariano's bill.

Patrick has identified his payment reform bill as his number one legislative priority for the fall, saying that while the state's landmark 2006 universal health insurance law has made care more accessible in Massachusetts, it has not made it more affordable.

Mariano and other House leaders have urged a go-slow approach on Patrick's bill, suggesting it might be late this year or even next year before it is considered.