Mayor Adams is ordering most city agencies to slash their budgets by another 4% on top of his administration’s two belt-tightening directives from last year, the Daily News has learned.

Jacques Jiha, Adams’ budget director, informed agency heads of the latest austerity measure in a letter Tuesday. Jiha wrote that the administration is baking the new cuts, known as a Program to Eliminate the Gap, or PEG, into the mayor’s executive budget proposal for the 2024 fiscal year, set to be released later this spring.

Jiha attributed the need for the additional budget trims to labor costs, proposed state budget cuts and the city’s migrant crisis, which he said had already cost $817 million as of the end of March. He said the total cost of accommodating migrants could reach $4.3 billion by July 2024, and that agencies must keep a lid on spending to hedge against that ballooning price tag.

“I know that achieving this PEG will not be easy, but it is critically important, and I have great confidence in this team’s ability to find creative and thoughtful solutions to the challenges we face,” Jiha wrote in the letter obtained by The News. “As always, I appreciate your commitment to ‘getting stuff done’ for New Yorkers.”

The austerity move drew an almost immediate backlash from progressive advocates and members of the City Council, which on Monday unveiled a response to the mayor’s preliminary budget proposal that included $1.3 billion in additional tax revenue that Speaker Adrienne Adams said could be used to reverse cuts proposed by the mayor.

In an uncharacteristically sharp rebuke, Speaker Adams and Council Finance Committee Chairman Justin Brannan questioned the administration’s estimate of how much the migrants could ultimately cost the city and predicted that the additional PEG spending curbs “will paralyze agencies, harm New Yorkers, and make it even more difficult for the city to successfully recover.”

“The administration continues to rhetorically convey ever-changing costs for supporting asylum seekers, despite never providing the Council with any substantive response to our repeated requests for evidence of these costs,” Adams and Brannan said in a statement.

“The fact remains that this administration has done nothing to address the structural problems that can alleviate some of the costs of caring for asylum seekers, despite repeated calls from the Council to implement urgent reforms.”

The NYPD is subject to the full PEG, and Jiha wrote that the only municipal agencies that will be spared the 4% budget shave are the Department of Education and the City University of New York. Instead, those two entities will face a 3% budget reduction measure to “minimize disruption to schools,” Jiha wrote.

The budget savings cannot be based on layoffs. However, in a shift from the administration’s previous two PEGs, Jiha indicated savings could be based on reducing services, though agencies “should avoid” doing so “where possible,” according to Jiha’s letter.

Agencies have until April 14 to come up with a plan for allocating the savings, Jiha wrote.

The rollout of the PEG comes at a time that some city agencies are struggling to fulfill their basic functions, including the Department of Social Services, which is failing to process most applications for food stamps and other benefits for low-income New Yorkers in a timely manner.

Ravi Mangla of the New York Working Families Party slammed the mayor for already cutting city agencies “to the bone” and predicted working people “will feel these cuts the most.”

Fiscal hawks had a much different take. Andrew Rein, president of the Citizens Budget Commission, said the measures outlined in Jiha’s letter are “overdue” and “probably not enough” to avert fiscal calamity in the years ahead.

Rein based his assessment on enormous budget gaps the city could potentially face as early as 2025 due to labor costs and the cessation of pandemic-related federal funding streams. Delaying measures like the ones outlined in Jiha’s letter would “increase the chance that the city barrels headlong into an impending fiscal wall and will have to make massive cuts in the future,” he said.

According to the fiscal watchdog agency Rein heads, the city now faces a $9.6 billion budget gap in 2025 and a $11.2 billion gap in 2027.

“That’s not very far,” Rein said. “You have to think about it longer term. They know we have an even bigger problem in the future.”

The mayor and the Council must reach an agreement on next fiscal year’s city budget by July 1.

“Mayor Adams has repeatedly said that we cannot sugarcoat the reality of the fiscal and economic challenges we are facing,” said Adams spokesman Jonah Allon.

“We face a perfect storm of factors — including near historic levels of spending as a result of billions of dollars in costs related to asylum seekers and the need to fund labor deals that are years overdue,” Allon said.

“At the same time, we are facing a slowdown in city tax revenue growth and what is predicted by financial experts to be a weakening of the nation’s economy. Ignoring these realities would be irresponsible.”

Tuesday’s order comes after Adams implemented two PEGs last year that subjected most agencies to two rounds of 3% budget shaves.

A Council member who’s involved in budget talks said that the mayor’s latest PEG will be devastating for city agencies.

“These agencies are already cut to the bone,” said the member, who spoke on condition of anonymity. “They won’t be able to survive another PEG.”