A fitness-obsessed NYPD official was allegedly caught working out when he should have been working — and now could find himself out of a job.

Lt. John Pizzano, a 20-year veteran, is accused of sneaking into the basement gym at 1 Police Plaza to pump iron while racking up overtime, according to law-enforcement sources and documents obtained by The Post.

Disciplinary charges allege that Pizzano, 42, scammed five hours and 25 minutes of OT during eight exercise sessions.

The buff cop was also allegedly seen in the gym on 12 other occasions when he put in for overtime, but it’s unclear how long those workouts lasted.

Pizzano’s base salary was $121,875 during fiscal year 2017, but overtime helped push his total pay to $176,668, according to the Empire Center’s SeeThroughNY Web site.

He took home $176,976 and $173,334 during fiscal years 2015 and 2016, respectively.

The charges against Pizzano allege that he failed to sign in or out of the NYPD gym, as required, 92 times, although most of those incidents took place during his regular working hours, when he was allowed to hit the weights.

He’s also accused of or leaving early on 195 occasions “without documenting activities, without supervisory approval and without submitting leave of absence reports,”

If found guilty of the departmental charges, Pizzano — who’s assigned to the NYPD’s Support Services Bureau, which manages the department’s vehicles and evidence warehouses — would face punishment that includes the loss of 30 vacation days or even forced retirement, sources said.

“They’re serious about bosses stealing time,” one source said.

Lieutenants Benevolent Association lawyer James Moschella said the union was “confident that Lt. Pizzano’s case is unlike other cases where members of the service were accused of stealing.”

“This guy puts in a lot of hours. Anytime a special project needs to be done for the Support Services bureau, Lt. Pizzano is on it,” Moschella said.

“I submit that it would be appropriate for a member who didn’t even take his meal to go clear his head and re-energize himself in the gym for 45 minutes before completing his tasks,” the lawyer said.

Pizzano refused a deal to avoid a departmental trial, sources said, but terms of the offer were unclear.

His trial was scheduled to start Thursday, but was postponed because he’s hiring a new lawyer, the NYPD said.

Pizzano was lauded earlier this summer for helping recover a stolen city vehicle, leading to the driver’s arrest, by relentlessly tracking it using license-plate readers — even on a day off, according to a Department of Citywide Administrative Services newsletter.

Pizzano, who remains on active duty pending the outcome of his trial, hung up on a Post reporter who reached him by phone.

His father, John Pizzano Sr., told The Post he had no idea about his son’s gym habit.

“He doesn’t talk about work,” the dad said.

Additional reporting by Reuven Fenton and Lia Eustachewich