PATH workers are snoozing away huge chunks of their regular shifts, using nap time to rack up big overtime pay, The Post has learned.

“Everybody sleeps,” an insider said. “Guys make big overtime by doing work for 40 minutes or an hour, then billing the Port Authority for four or five. That’s been going on for years.”

The workers’ on-the-job dozing is under investigation by the PA inspector general, an agency spokesman said.

The PA, which operates the rail system, prohibits PATH workers from sleeping on the job — but the rule is routinely ignored, eyewitnesses said.

“You come in, you sit down, your TV goes on, your head goes back, and you fall asleep,” the insider said.

“Other guys set up a cot and take four-hour, five-hour naps.”

The Post obtained photos of four PATH employees sleeping in the “consolidated shop,” a Jersey City building in an industrial area off Academy Street. It is a headquarters for mechanics, electricians and carpenters who repair tracks and install or fix equipment in stations.

The photos show three employees reclining on folding lounge chairs next to lockers or showers. A fourth stretches out on the floor next to a locker-room bench. All curl up with blankets and pillows.

‘Guys make big overtime by doing work for 40 minutes or an hour, then billing the Port Authority for four or five.’

“You walk into the locker room at 2 to 3 in the morning, it’s not uncommon to see eight or 10 guys asleep,” the source said.

For privacy reasons, security cameras are not installed in locker rooms or showers, so the sleepers can’t be caught on video.

Supervisors tacitly condone the snoozing — and even join in, whistleblowers charge.

One foreman lays a mattress pad, pillows and blankets over his desk before ​turning in for the night — all on the dime of people who pay PA tolls, train fares and other charges, a source said.

It’s a clear violation of regulations. “Employees shall not sleep nor give the appearance of sleeping while on duty,” the PATH Book of Rules says.

PA spokesman Scott Ladd said the agency’s inspector general was investigating the allegations but refused to comment further.

The abuses have “gone on for years,” said a PATH employee who asked to remain anonymous.

Besides sleeping, workers take long lunch breaks, watch TV and fiddle with their cellphones while piling up regular and overtime hours.

“They’ll give you a window of normally four hours of overtime to complete a work order. If you get it done in 15 minutes or an hour, the overtime should end. But that never happens.

Everybody will say it lasted four or five hours,” the employee explained. “Management just lets it happen.”

Five years ago, New York state Comptroller Thomas DiNapoli complained that overtime pay “flows like water” at the PA. The bi-state agency promised it would try to curb the expense.

Last year, the PA paid out $221 million in overtime, or 17 percent of total labor expenses, its Web site reports.

At the Jersey City shop, 480 PATH workers in 2015 raked in $8.6 million in OT, or 20.4 percent of the total $42 million payroll.

That was down from 2014, when 475 workers there collected $11.2 million in overtime, or 25.5 percent of their $42 million pay.

The PA, meanwhile, has imposed a series of toll hikes since 2011. Cash tolls on its bridges and tunnels have gone from $8 to $15.

The PA, which has hinted at more hikes in 2020, says the revenue is needed for infrastructure improvements and big projects like the World Trade Center site.

Additional reporting by Joshua Tanzer