Mayor Bill de Blasio and wife Chirlane McCray’s billion-dollar mental health program has failed New York City, according to a damning new report by Public Advocate Jumaane Williams.

“The City’s current approach to addressing mental health crisis is failing,” Williams says in the 21-page report released Wednesday.

“We do not have enough systems in place to help prevent New Yorkers with mental health issues from experiencing crisis, and when these crises do occur, we respond to them punitively,” he added, citing the 15 shooting deaths of mentally ill people by police over the past three years.

Though the report never specifically mentions Thrive NYC, it amounts to an implicit indictment of de Blasio and McCray’s signature initiative and even singles out some of its key programs for criticism.

McCray rolled out the signature policy in November 2015, calling the costly program a “plan of action [that] will guide the city toward more an effective mental health system.”

Nearly four years later, Williams wants an overhaul of the city’s approach toward mental health, noting that calls for what the NYPD labels “emotionally distressed persons” have nearly doubled between 2009 and 2018.

“Despite the increased prevalence of these calls, New York City has yet to develop a comprehensive strategy for responding to people experiencing mental health crises,” Williams says.

He adds that a ThriveNYC program meant to prevent deadly encounters between cops and the mentally ill operates too slowly to be effective.

Under ThriveNYC, the Mobile Crisis Team program dispatches groups of cops paired with health professionals like nurses or social workers to help the homeless and mentally ill.

But Williams found the “Crisis Teams do not currently have the resources to respond immediately to crises, instead responding within 48-hour window of time from when the initial referral takes place.” He says the city must improve response times and integrate the program into the 911 call system.

The NYPD also needs to accelerate its “Crisis Intervention Training” for officers, Williams says. Fewer than a third of cops have completed the training.

Other recommendations in the public advocate’s report include opening “mental health urgent care centers” where people in crisis could stay short-term instead of being admitted to a hospital, and “drop-in centers” where homeless New Yorkers could get food, visit with a social worker, and get referrals to other resources.

A de Blasio spokeswoman said: “This issue is of critical importance to the administration. As the public advocate knows, the city will announce significant new strategies to better prevent mental health crises soon.”

Williams also released a statement that said McCray “deserves credit for using her platform to raise the issue of mental health.”

“While Thrive continues to work to find the best way to help New Yorkers facing mental health challenges, our city can and must to do more to address the way we approach people in crisis,” he added.