AUGUSTA — Expanding Maine’s Medicaid system under the federal health care overhaul would cost an estimated $807 million and add 266,000 people to the state’s Medicaid rolls over the first decade, crowding out funding for the elderly and disabled who need it the most, officials said Friday as they revealed results of a study commissioned by Gov. Paul LePage’s administration.

The report by the Alexander Group, led by Gary Alexander, who as welfare chief in Pennsylvania came under fire from advocates for the poor for slashing Medicaid spending, concluded that Medicaid enrollment would grow from 318,000 to about 382,000 in Maine over the next 10 years even if the state does nothing. The figure would grow to 584,000 under a Medicaid expansion and nearly 100,000 new enrollees could join the program within the first two years, the report said.

The findings, coming days after hundreds packed into the Statehouse to urge lawmakers to expand Medicaid under the Affordable Care Act, could fuel further resistance from Republicans who were already weary to do so. But Democrats say the report is ideologically and politically driven and pointed to studies showing the state saving $690 million over the next decade with the expansion of Medicaid, or MaineCare as it’s called in the state.

“Maine people should see this for what it is: yet another political excuse to deny and delay health care to tens of thousands of Mainers,” said Democratic House Speaker Mark Eves of North Berwick.

Health and Human Services Commissioner Mary Mayhew told reporters Friday that the state can’t count on promises of additional federal funding that may not materialize, pointing to the federal government’s reduction of Medicaid funding over the last 25 years and the government shutdown in October that froze federal funds from coming into the state for days.

Mayhew said it would be irresponsible for the state to expand Medicaid to able-bodied adults while thousands of disabled and elderly people but are on waiting lists for in-home services or around-the-clock care in the Medicaid program. There are more than 3,900 people waiting for services today and that would only grow under the expansion, she said.

“MaineCare and Medicaid were intended to be a safety net for our neediest but it has turned into a tightrope that vulnerable Mainers are falling off every day,” she said. “We cannot in good conscience ask the taxpayers of Maine to foot this very large bill to care for younger non-disabled adults when we are failing to meet our mission today.”

In addition to studying the feasibility of the Medicaid expansion, the department hired the Alexander Group to address financial challenges in the state’s Medicaid program and to help the state obtain flexibility from the federal government in running the Medicaid program. Only the Medicaid expansion portion of the report was made public Friday.

The Republican governor told reporters recently that he had initially offered Alexander the job as health department commissioner, but that Alexander turned it down because the salary was too low.

Democrats say Alexander’s contentious policies have failed in other states and will only harm the most needy in Maine. While he oversaw Pennsylvania’s Department of Public Welfare, the state cut a cash program for some disabled adults and tightened eligibility rules for food stamps. The department was also accused of improperly kicking some people off Medicaid after nearly 90,000 children disappeared from Medicaid rolls.

But whether or not the state expands Medicaid, the financial future of the program is gloomy, Alexander said. He said growth of the state’s Medicaid program is already exceeding the annual growth of the state budget.

The state’s DHHS budget currently has a roughly $100 million deficit, Democratic leaders said Friday, and LePage’s administration says most of that can be attributed to Medicaid.

“There is still going to be a problem ”“ with or without the state expanding Medicaid,” Alexander said.