AUGUSTA, Maine — A Republican representative’s proposal to provide services to hundreds of people with disabilities on waiting lists would add a $75-million-a-year price tag to a bill that would expand Maine’s Medicaid program under the federal Affordable Care Act.

Rep. Deborah Sanderson of Chelsea said Tuesday she plans to attach two amendments to the Medicaid expansion bill pending in the Legislature. Under those amendments, hundreds of people with developmental disabilities on state waiting lists for services in their homes and communities would receive those services by the start of July.

The move, however, would add a hefty price tag to a bill that currently carries no official price tag and promises the state savings over the next three years, the period during which the federal government promises to cover 100 percent of Medicaid expansion costs. The cost would almost undoubtedly hold up the bill as appropriators in the Legislature search for funds that are likely unavailable.

Democrats said the proposal was an attempt to undermine the Medicaid expansion bill.

“It sounds to me that, if this comes with a huge price tag, it’s a way of them trying to undermine the whole Medicaid expansion and make it not happen,” said Rep. Linda Sanborn, D-Gorham, who’s sponsoring the expansion bill. “I think it’s both somewhat devious and ill-informed. We need to take care of the folks we can expand with, too.”

Republicans opposed to expanding Medicaid in Maine, including Gov. Paul LePage, have frequently pointed to the existing wait lists for services as a reason they can’t support the Medicaid expansion, which would benefit adults without children and parents of dependent children who earn up to 133 percent of the federal poverty level, or $20,628 for a two-person household.

“I would like to know when our elderly and disabled will stop getting shoved to the back of the line so that young, able-bodied people can get free health insurance,” Sanderson, the ranking Republican on the Legislature’s Health and Human Services Committee, said in a statement released by the House Republican office. “It’s unconscionable to expand welfare to young adults while Maine’s most vulnerable are left out in the cold.”

Sanderson plans to introduce the two proposals on the House floor when the Medicaid expansion bill returns to that chamber, which could be as soon as Wednesday. Her amendments would require the Department of Health and Human Services provide services to hundreds of elderly people and people with intellectual and physical disabilities and autism — and pay for them.

The people on wait lists for services do receive health insurance coverage through the state’s Medicaid program, MaineCare. The state has had insufficient funds, however, to provide them with additional services in their homes and communities. A group of adults with autism and intellectual disabilities recently filed a lawsuit against the LePage administration in Kennebec County Superior Court for failing to provide housing and other services promised under MaineCare.

The two-year budget package headed to the full Legislature includes about $6.7 million to remove about 85 people from wait lists for services.

The Medicaid expansion, meanwhile, would provide coverage for about 50,000 adults without children who would become eligible for coverage if Maine expands Medicaid. The expansion would also prevent about 25,000 parents and childless adults from losing their Medicaid coverage starting Jan. 1, 2014.

The bill has passed both the House and Senate, but not with enough support to override a near-certain veto by LePage.