The MTA faces dire fiscal straits when COVID-19 emergency funding dries up — and may be forced to scale back sorely-needed repairs if Congress fails to pass the $1.2 trillion bipartisan infrastructure bill, State Comptroller Tom DiNapoli said Tuesday.

Transit officials face a $1 billion deficit come 2025 — yet plan to increase spending by an average of 4.2 percent per year, more than the expected rate of inflation, DiNapoli said in his annual review of the $19 billion-per-year transportation authority.

MTA leaders have struggled to keep the agency afloat since COVID-19 decimated rider fares, which have only recovered to just 50 percent of 2019 levels. Officials were only able to close the massive revenue hole thanks to $15 billion in federal relief and by borrowing $2.9 billion that had been intended for capital improvements like maintenance and subway expansion.

As a result, if Congress fails to pass its infrastructure deal, the MTA will be forced to scale back its ambitious, $55 billion five-year capital plan, DiNapoli warned.

“Bringing riders back, protecting against extreme weather and maximizing new sources of revenue are all challenges the MTA needs to address before emergency federal funds dry up in 2025,” he said in a statement. “After that, the MTA faces enormous budget shortfalls that could harm the regional economy with no easy solutions.”

Much of the financial outlook depends on ridership, the report said.

If workers in 2022 work from home an average 1.5 days per week, the MTA will exceed its revenue projections by $300 million — but if they stay home four days per week, the MTA will be short $500 million compared to its financial plan.

Of particular concern to the comptroller is the MTA’s debt, which currently eats up about one-fifth of rider fares. Without new sources of money or budget cuts or both, the MTA will have to borrow even more to pay for short-term maintenance and cleaning, he said.

To close the budget gap, officials may be forced to scale back its capital program or scale back service to meet current demand, the report said. Either option could hamper ridership — and create a “death spiral” of worsening service leaders and fewer fares.

“If you’re trying to bring rides back on board, cutting service is going to have the opposite effect. Cutting service and raising fares should both be off the table now,” said Lisa Daglian of the MTA’s in-house citizen advisory committee.

DiNapoli also skewered the MTA for declaring victory on its so-called transformation plan, which launched in 2019 with the goal of cutting jobs from administrative roles.

A whopping 84 percent of the 2,725 positions cut under the plan were in maintenance or operations, the report said. The drop in personnel created to a bus driver and train operator shortage that has caused significant service disruptions.

Officials have responded by fast-tracking the hiring of hundreds of workers — negating the cost-savings of the transformation plan.

“Any increased hiring to meet operational and maintenance needs could also erode savings from the elimination of these positions, raising questions as to whether the savings the MTA has achieved from the transformation plan will be recurring after 2021,” the report said.

The MTA did not immediately return a request for comment.

“Predicting the pace of post-pandemic ridership recovery is difficult, but as revenue levels emerge and stabilize all stakeholders will need to evaluate strategies to address the deficit created by COVID’s impact on MTA farebox revenues,” MTA rep Aaron Donovan said in a statement. “For its part, the MTA will continue to identify cost efficiencies while aligning service to meet public needs.”