The head of New York City’s troubled jails spent a quarter of 2016 in his home state of Maine, driving his government-issued vehicle and charging taxpayers to fill up the gas tank in violation of ethics rules, according to a report released Friday by the city Department of Investigation.

Joseph Ponte, appointed Department of Correction commissioner in 2014, was out of town for about 90 days, during jail incidents that included stabbings, slashings, staff and inmate deaths, and an escape, and “he never actually responded from Maine to any DOC emergency,” the reason top officials are given take-home vehicles at city expense, the report said. The vehicle was used almost exclusively for his out-of-town trips in 2016, totaling 18,500 miles.

The probe, which began after an anonymous tip, also “revealed systematic misuse of city vehicles” by 21 correction employees who “frequently” used their vehicles to travel to the Hamptons, the Poconos, Mohegan Sun casino, the Riverhead outlets, and to shuttle friends and family to airports and more. Tolls, gas and mileage, the report found, were often charged to taxpayers.

Ponte was brought in by Mayor Bill de Blasio to try to fix Rikers Island, the city’s main jail complex, which the U.S. Department of Justice said was beset by “a deep-seated culture of violence” by guards and inmates.

A deputy commissioner who oversees the department’s internal investigations and already had been fined $1,500 by the Conflicts of Interest Board for related conduct, still used his vehicle to go golfing, transport his wife when they’d go out to dinner and travel to Westchester on personal business, most of which occurred after the first fine. Ponte’s chief of staff went to a friend’s birthday party in Virginia in the car, on the clock.

Neither Ponte nor his subordinates could be reached for comment, but de Blasio shrugged off the allegations, arguing that Ponte had followed “guidance.” De Blasio did not give the source of the “guidance” allowing the behavior.

“I just released an $84 billion budget, so the fact that there’s $1,000 in gas expenses, you know, it’s put in perspective,” de Blasio said Friday on his weekly #AskTheMayor call-in radio show on WNYC. “But whatever was done here is going to be made whole.”

But less than an hour after those remarks, de Blasio’s own commissioner of investigation — his former campaign treasurer, Mark Peters — said, “City Hall is misinformed” and “our investigation conclusively demonstrated that Commissioner Ponte and others did not receive official ‘advice’ that they could use their cars for personal trips out of state.”

“There can be no defense of this behavior and City Hall harms government integrity by even trying,” he said. De Blasio spokesman Eric Phillips dismissed the comment in a tweet: “snooze.”

advertisement | advertise on newsday

Dick Dadey, executive director of the good-government group Citizens Union, said Ponte should be fired.

He said the mayor’s ridicule of the amount of money Ponte spent on gas for personal reasons — about $1,000 — is alarming.

“A thousand dollars to most New Yorkers is a significant amount of money,” Dadey said, “and should not be so easily dismissed.”