AUGUSTA — As congressional efforts to change former President Barack Obama’s health law sputter, a push to expand Medicaid in Maine has opponents raising questions about the source of future federal funding.

Maine voters are set to consider a Nov. 7 ballot question to require the state to apply for a Medicaid expansion for adults under 65 with incomes at or below 138 percent of the federal poverty line.

Currently, 31 states and Washington have used federal dollars to expand Medicaid coverage, and Maine is the only New England state not to do so.

Liberal groups and health care providers say expansion could help roughly 70,000 low-income Mainers struggling with medical expenses and opioid addiction.

Opponents include Republican Gov. Paul LePage, who has rejected Medicaid expansion five times with Republican allies ,and traveled to Washington this year to lobby for Maine and federal work requirements for Medicaid recipients.

Both sides accuse the other of skimping on the facts.

Maine’s ballot question would expand coverage to adults under 65 who earn below $16,000 for a single person and $22,000 for a family of two. Currently, 19- and 20-year-olds, individuals with disabilities, the elderly and certain low-income parents qualify for MaineCare.

David Farmer, a spokesman for the expansion campaign, said it will “reduce the number of people without health insurance, it will create jobs.”

The federal Centers for Disease Control and Prevention called Maine’s uninsured rate of 8.8 percent in 2015 an all-time low, but Maine Hospital Association president Steven Michaud has said state eligibility rules cut MaineCare enrollment by 75,000 people in recent years.

Michaud said that move shifted costs to Maine hospitals, which are providing about $250 million a year in charity care while Medicaid payments to hospitals are decreasing.

Expanding Medicaid is estimated to cost Maine $54 million each year once it is fully implemented, according to the ballot question’s fiscal note.

That figure includes $27 million in estimated savings and the cost of 103 new state positions to administer the expansion. The federal government would chip in $525 million each year, and lawmakers would have to appropriate the $54 million if the ballot question passes.

Obama’s health care law allowed states to expand Medicaid coverage and receive enhanced federal funding that recent House and Senate Republican bills would have curtailed. Under the law, the government share dropped to 95 percent this year and drops to 90 percent in 2020.

Maine won’t receive that extra federal funding for a chunk of low-income Mainers under an expansion because the state previously expanded Medicaid, then curtailed coverage. A failed Maine bill estimated that the state would instead receive the regular match of about 62 percent for a quarter of approximately 79,000 eligible Mainers.

The campaign behind the expansion push has reported more than $130,000 in contributions and in-kind support from Maine progressive groups, residents and the out-of-state Fairness Project, which is backed by the Service Employees International Union and supports ballot initiatives nationwide.

Opponents have not formed a formal campaign. LePage, Maine Republican Party Executive Director Jason Savage and the Maine Heritage Policy Center are warning the state’s 2002 Medicaid expansion led to unexpected enrollment and annual shortfalls of $50 million to $100 million.

Savage said: “$500 million is a lot of money to be paying with in the state budget with no certainty” about the federal health care law’s future.

A 2012 Harvard School of Public Health study found expanding Medicaid reduced mortality, increased access and coverage and improved health care outcomes in three states including Maine.