Retired subway and bus operators are up in arms about a change to their health benefits in the most recent contract between the Transport Workers Union and the MTA — but the union says the contract improves health coverage for retirees and differs significantly from a city government plan currently facing legal challenges.

The deal — tentatively struck last month but still in need of full ratification by TWU membership — would remove the option of traditional Medicare coverage for retired workers at the state-run MTA.

The union’s two Medicare Advantage plans, both administered by private insurance giant Aetna, would remain as the only premium-free health coverage options for MTA retirees.

Unlike traditional Medicare, Advantage plans are administered by private health insurance companies. The plans are also subsidized by federal dollars at a higher rate than traditional Medicare options, producing budget savings for local governments.

“This is a blatant, not-so-professional attempt to deceive retirees and put them in a sub-standard healthcare system,” Anthony Tousis, a retired bus driver from Queens, told the Daily News on Monday.

The plan comes as Mayor Adams faces renewed legal threats over his administration’s plan to move retired city government workers into a privatized Advantage plan.

Last month, a group of city retirees filed suit against the mayor, calling his attempted Medicare Advantage swap “an unjust bait and switch” that violates various local laws in an effort to generate savings for the city.

The group of retired teachers, cops, firefighters and other city workers has pointed to studies from the U.S. Department of Health and Human Services inspector general that show Advantage plan holders can be denied “medically necessary care,” in part because of private providers’ requirements that various procedures be “pre-authorized.” The same group of retirees successfully blocked Adams’ administration in court last year from enacting its first Advantage plan.

But a spokesman for TWU Local 100 — which represents some 40,000 state employees who work for the MTA — told The News that the Medicare Advantage options in its tentative contract were better than the city’s, and would provide better coverage for retired workers than the outgoing traditional Medicare plan.

Over 99% of retirees using the traditional Medicare plan are using doctors who would be accessible under the Advantage plans, TWU spokesman Pete Donohue said.

The Advantage plans have been part of the union’s benefit package for years, he added, and coverage would not be reduced going forward.

“This is not the city plan, far from it,” reads a flyer sent to TWU 100 members. “There is no comparison. The coverage for our retirees is far superior.”

“Unlike other unions, we have bucked the downward spiral of care for our Medicare Eligible retirees,” the union said in a statement to members over the weekend. “We successfully demanded that millions of dollars in federal funds go to TWU Enhanced Retiree Medical Coverage [the union leadership’s name for Medicare Advantage] with two Aetna Options.”

The statement goes on to say that the most expensive of the two options would include zero co-pay for generic drugs, primary care, preventative care, and hospitalization, as well as zero co-pay for emergency room visits — an improvement over the outgoing traditional Medicare plan.

If the contract is ratified, the new benefits plans would go into effect next year.

Retirees are ineligible to vote on contracts, according to the union’s bylaws.

“Here we are — the union decides our health benefits, and we have no vote on the matter,” said Mike Tutrone, who was director of the union’s retiree’s association until three months ago. “How democratic is that?”

Of the roughly 19,000 retirees currently receiving health benefits from the union, about 14,000 are enrolled in traditional Medicare, Tutrone said.

Tutrone, who said he uses an Advantage plan himself, told The News he opposed the removal of traditional Medicare option.

“The union disenfranchised 14,000 retirees,” he said. “Retirees are getting screwed here.”

Tom McNally, a retired MTA bus operator who also worked for the TWU for nine years, said he feels betrayed by his union.

“They’re screwing us retirees to give the active members a raise,” McNally, 65, said, adding that he’s been told $36 million will be saved per year on health care costs thanks to the Medicare Advantage switchover. “It’s all about money.”

At least one active member — Seth Rosenberg, a subway operator based in Coney Island who has worked for the MTA for 17 years — seemed set to vote against.

“When I found out what was going on with the city workers, I thought it was awful — and then when I found out our union is trying to sell out its own retirees, I became furious, because we are all going to be retirees one day,” Rosenberg said.

“The fact that the union leadership is pitching this as a good thing is an abomination.”