BOSTON - In the midst of a messy and contentious battle to replace the Affordable Care Act in Washington, some Massachusetts lawmakers are proposing a solution they believe is long overdue: A single-payer system.

“The important distinction of single-payer is that it guarantees coverage as a right, but it also does it much less expensively than the current system,” said state Sen. Jamie Eldridge, D-Acton, the lead sponsor of a bill that proposes to bring a single-payer financing system to Massachusetts.

The concept is relatively simple, built upon the idea that health care is a right, not a privilege. Every resident should have access to health care, and employers and employees pay a payroll tax instead of paying insurance companies. The government is the so-called “single payer,” directly reimbursing providers.

Proponents say such a system would result in significant savings; it would cut out the administrative costs involved with private insurance companies, while ensuring access to health care would prevent patients from waiting until they were in need of expensive hospital services before seeking care.

Total health care costs in Massachusetts rose by $2.6 billion, to $57.4 billion, in 2015, an increase of 4.1 percent from 2014, according to the Center for Health Information and Analysis, a state agency. The American Health Care Act, the plan Republicans are pushing to replace the ACA, is estimated to reduce the federal deficit by $337 billion over the next 10 years, but will leave 24 million people without health insurance, according to the Congressional Budget Office.

“There’s an added urgency and that’s why there’s a lot more interest in the [single-payer] bill,” said Mr. Eldridge. “People are looking at what the Republican Congress and President Trump are doing to the Affordable Care Act and saying: ‘Well, if this is going to happen at the federal level, what can we do on the state level to both guarantee health care access and lower cost?’”

Not everyone agrees.

Eric Linzer, the executive vice president of the Massachusetts Association of Health Plans, which represents many of the largest insurers in the state, said a single-payer system would reduce access to care, undermine quality, increase wait times and hinder innovation.

“It would really shortchange Massachusetts consumers,” he said.

He also thinks single-payer will do little to ameliorate the issue of rising health care costs. Instead, the state should focus on addressing the prices charged by providers, provider mergers and acquisitions and the rising costs of prescription drugs.

Katharine London, a principal consultant at the University of Massachusetts Medical School’s Center for Health Law and Economics, was muted in her opinion of Mr. Eldridge’s bill, calling it “aspirational.”

The bill, which proposes establishing a health care trust that would be responsible for collecting and disbursing funds needed to provide health care services for Commonwealth residents, would be funded through a 10 percent payroll tax — 7.5 percent for employers and 2.5 percent for employees — and a tax of 12.5 percent on unearned income.

Ms. London, who was involved in the fiscal analysis of Vermont’s failed single-payer effort, said the 10 percent payroll tax struck her as low.

“Moving from a privately financed system to a publicly financed system is incredibly complex,” she said, adding if Massachusetts truly wants to move towards single-payer, an incremental approach would be better. She suggested creating a public plan and giving residents the option to choose it.

“If you build something people really like, they will move into it. Then you can start to phase out some of the private,” she said. “If it’s lower cost and better quality, people will choose it.”

State Sen. Anne M. Gobi, D-Spencer, one of the co-sponsors of Sen. Eldridge’s bill, acknowledged the complexity of setting up a government-financed health care system.

“Change is always very difficult,” she acknowledged. “This is a totally different way of looking at how health care would be delivered. It would require drastic overhauls.”

However, she said she thought the time was ripe to have a serious discussion about implementing single-payer.

“There’s a lot of uncertainty in Massachusetts with what’s happening on the federal level,” she said, referring to the Republican plan to overhaul the current health care law.

“I do think the timing is right,” she said, “to at least have for a very serious conversation on this and to look at how this could be implemented.”