Mayor de Blasio on Thursday acknowledged that the awarding of hefty raises to hundreds of housing workers over the summer wasn’t done appropriately — and that the salary increases will not go ahead as planned.

The Department of Housing Preservation and Development awarded raises as high as 40 percent to nearly 300 tenant-resources workers on July 1 — but without getting approval from the city’s budget office.

“I think this was a bureaucratic foul-up, [that] is the bottom line. And it’s rare — I don’t remember anything like this in many years working in government,” the mayor said after an unrelated press conference in Brooklyn.

“It was wrong. I think it was not an ill-intentioned mistake, but it was a mistake that shouldn’t have happened and we’re going to fix it.”

City and union officials are set to meet in the coming days to work on a solution that doesn’t involve simply revoking the raises.

Many of the HPD staffers saw their baseline salaries boosted from roughly $35,000 to $50,000 as a result of the unauthorized hikes.