Mayor Eric Adams came under fire Friday over his plan to slash funding for city cops and other essential services — while hoarding $15 billion to pay for new municipal union contracts.

“The NYPD is the last agency I would cut,” fumed City Councilman Robert Holden (D-Queens). “We want to bring New York City back. We’ve got to drop the crime. We need more cops. We have fewer.”

Holden added, “We need more technology, more cameras. We want more people to take the subway, go to work.”

City Council Minority Leader Joe Borelli (R-Staten Island) also invoked the estimated $1 billion annual cost of the city’s spiraling migrant crisis, which Adams didn’t include in the proposed $102.7 billion budget for fiscal 2024 that he unveiled Thursday.

“It’s troubling that out-of-control migrant spending is placing pressure on our essential services. I think it goes deeper than the standard trim,” Borelli said.

“I’m very concerned about any cuts to the police department, as night after night, my social media feed is filled with people getting their cars robbed and their homes broken into.”

Borelli added: “I need more cops, not less.”

Councilwoman Joann Ariola vowed to oppose Adams’ spending plan.

“You’re cutting services from police, fire, sanitation, mental health and youth services,” she said. “We’re going to bring back these numbers to where they should be. I’m not a fan of cutting any of our services.”

Ariola specifically cited Adams’ plan to reduce spending on sanitation from $1.93 billion to $1.82 billion, saying that “we’re just getting the city clean again.”

Adams’ plan would reduce funding across the board for every city agency, including the NYPD, which would have its budget cut by from $5.59 billion to $5.44 billion. The schools budget — the city’s largest — would also be slashed from $31.25 billion to $30.74 billion.

But Adams has also proposed increasing by 12.4% the amount of money in the city’s “Miscellaneous” fund, which the independent Citizens Budget Commission said is primarily reserved to cover raises and back pay for members of the city’s labor unions, which are all working without contracts.

The fund is also used to pay for increases in the cost of benefits, including health insurance.

CBC president Andrew Rein said Adams would need to hold the line on spending and “aggressively” manage and restructure government services if he wants to avoid a serious fiscal crisis.

“The gaps in the out years are huge. We’re going to hit a wall. Hitting a wall is hard,” he warned.

During a Friday afternoon appearance on the Brooklyn-based online radio station “Caribbean Power Jam,” Adams likened his budget plan to the recurring message he got from his mother while growing up.

“Our national economy is uncertain,” he said. “We better be smart, fiscally prudent and willing to understand, as Mommy says, ‘This is what we brought in. And this is what we have in bills.’”

Adams added: “And until then, we gotta get out of these turbulent waters. I have to make some tough decisions.”