NYCHA workers transformed a Bronx housing project into their own personal sex club — engaging in wild, boozy orgies inside offices, the groundskeepers shop and even empty apartments, sources said Monday.

“[It happened on] overtime, during working hours, after working hours, any day or any time of the day,” said Throggs Neck Houses Tenant Association President Monique Johnson. “I now understand why work wasn’t getting done.”

Things got so bad earlier this month that NYCHA had to transfer the entire complex staff — roughly 40 people — to another location as a result of the romps.

“There was a lot of people included,” Johnson told The Post. “Supervisors were allegedly having sexual relations with caretakers. There was drinking and sexual acts going on…More playing, and less working.”

At any given time, staff members were known to find up to a dozen people taking part in the orgies, according to sources.

Some workers got so fed up with the debauchery that they secretly shot videos and photos as evidence — which they later offered up to NYCHA management, the sources said.

Complaints were filed with the Department of Investigation, which recommended NYCHA take disciplinary action on Aug. 15, per a city official.

NYCHA General Manager Vito Mustaciuolo ordered the Throggs Neck staff off the premises on Friday and asked everyone to turn in their keys — even the workers who weren’t involved.

“It’s bittersweet,” Johnson said. “It gives us the opportunity to start fresh, start anew. But you have workers that have been here for 20-plus years. They had nothing to do with these allegations, and now they’ve been uprooted. I feel sad for them.”

NYCHA spokesperson Robin Levine told The Post that the department had “long-standing concerns about management and performance issues” at the Throggs Neck houses.

“Those concerns, coupled with troubling allegations of misconduct, are why the staff was reassigned,” Levine said.

The sexcapades are the latest black eye for the embattled Housing Authority.

Mayor Bill de Blasio agreed to pay as much as $2.2 billion over the next decade to settle charges that it mounted a years-long cover-up to hide its failure to conduct required lead inspections, potentially left hundreds of kids exposed to the toxic substance, and the crumbling and toxic conditions in its hundreds of complexes scattered around the city.