The city has launched an investigation into harassment that 311 users said they faced after submitting illegal parking reports to the NYPD, ratcheting up the scrutiny of the police response to driver misconduct complaints.

A spokeswoman for the city’s Department of Investigation confirmed late Friday that agency staffers were probing the allegations — two months after Streetsblog reported on them as part of a broader investigation into the police handling of 311 complaints. The spokeswoman did not provide further details about the city inquiry, which was first reported by The Atlantic last week.

Users of 311 told Streetsblog they’ve received barrages of phone calls in the middle of the night from blocked phone numbers after submitting reports about cars obstructing bike lanes, using dubious parking placards or flouting other traffic laws. Some anonymous callers left voicemails that contained only heavy breathing or a man repeating a 311 user’s name over and over. The recipients said they believe it was cops trying to intimidate them into no longer filing complaints.

Another 311 user received an intimidating text message from an unidentified sender after Streetsblog reported on an insult-laced exchange he had with a city cop over his 311 complaints.

Even Council Member Robert Holden (D-Queens) has said he’s received 3 a.m. calls after filing 311 complaints — in his case from cops who identified themselves. He called the late-night calls “inappropriate,” and accused the NYPD of not taking the issue seriously.

Those allegations fit into a broader pattern of police neglect of 311 reports on illegal parking, chronically reckless driving and abandoned vehicles, Streetsblog found. This disregard has fostered a culture of lawlessness on city streets as traffic deaths climb to their highest point in years.

Streetsblog’s investigation prompted demands from Mayor de Blasio and Council Member Ben Kallos (D-Manhattan) for the city to investigate the harassment allegations in particular.

“Whether [the harassing phone calls are] coming from a city employee or someplace else, it’s not good,” the mayor said in October. “What we need to know is what happened in those cases.”

Evan Thies, a spokesman for incoming-Mayor Eric Adams, has not responded to requests for comment on Streetsblog’s stories on the issue.

The City Council is also looking into the NYPD’s handling of 311 complaints. Over the summer, cops ignored more than a dozen 311 complaints about illegal parking filed by Council investigators despite saying they had resolved them them. Council members rebuked the police over the issue at a hearing in October.

Police brass vowed at the hearing that the NYPD takes 311 seriously, but the department blew an October deadline to turn over relevant records to the Council, leading the lawmakers to issue a subpoena. A Council spokesperson told Streetsblog on Monday that “the NYPD has agreed to provide the subpoenaed materials” but did not answer other questions.

On Monday, Chong Bretillon, who said she received half-a-dozen intimidating, anonymous calls after filing 311 complaints, said she was glad the city is finally looking into the issue.

“This is good. I hope they get punished,” she said of the anonymous callers, who she suspects to be police officers. Those calls make “it plainly obvious that my concerns are not being taken seriously, that they’re trying to intimidate me and just trying to discourage me from continuing to file these complaints,” she said.

The NYPD did not respond to a request for comment.