A day after Mayor de Blasio promised to change the “reality” of syringe-strewn St. Mary’s Park “very, very quickly,” there was no panic in needle park.

Instead, junkies confidently shot up a storm at the Mott Haven green space on Saturday, brazenly tossing their used spikes on the ground instead of in the city’s special green disposal boxes.

A Post photographer and reporter witnessed up to five addicts at a time shooting up on park benches or a rock outcropping.

No police presence was seen in the park from 7:30 a.m. until about 11 a.m., when an NYPD SUV first cruised through.

After The Post began making inquiries with City Hall, a police van appeared around 2 p.m., and cruised through the park without stopping. There were not other city agencies seen doing outreach, or cleaning up the mess being left behind by the addicts.

At a Friday press conference, Hizzoner huffed about the brazen drug users, “I don’t accept what’s going on in that park … I don’t accept it from a health point of view or from a policing point of view. We are going to change that reality very, very quickly.”

Local residents on Saturday weren’t holding their breath.

“It’s going to take forever. He probably won’t make no change at all,” said a 23-year-old mom who was walking with her 4-year-old daughter along a sidewalk bordering St. Mary’s. The mom refuses to enter the park because she fears the “drug people.”

“You don’t know if you gonna step on a needle that could contain HIV,” she said. “A kid could step on it.”

Norma Lopez, 35, who was trying to enjoy the 35-acre park with her bike-riding 6-year-old daughter, said, “You see the police cars but they don’t stop really. I see the [junkies] hanging around and [the cops] don’t even stop to examine or to tell them to go away. They just don’t do it.”

Monserrate Deleon, 50, is not confident the mayor will tackle the problem.

“[The cops] will show their face for a little while … [de Blasio’s] not gonna fix it … He already done his second term so he’s not going to do nothing,” he said.

The city announced Friday that it plans to hire six workers next month — at an annual cost of $350,000 in salaries and benefits — to scrub the fields of syringes littering drug-infested South Bronx Parks.

The Parks Department also said it would spend $450,000 a year to pay for specially trained mental-health workers to start cleaning out the mayor’s needle-disposal boxes and “providing life-saving services and connections to treatment and other care” to the addicts they meet in the parks.

Both announcements came after The Post revealed how de Blasio’s controversial, syringe-collection program racked up a dismal 11 percent success rate during its first six months.

One drug user in hardest-hit St. Mary’s Park said the city was “giving permission” for people to shoot up by installing the needle-disposal boxes.T

An NYPD spokesman on Saturday said that patrolling St. Mary’s was a “priority.”

“The NYPD is deploying steady sectors, response autos and directed NCO (Neighborhood Coordination Officers) patrols to ensure safety and quality-of-life at St. Mary’s Park.”

De Blasio spokeswoman Jane Meyer said, “Last month, we deployed teams across the Bronx to engage with people with substance use disorders and connect them to resources. Effective immediately,

we are increasing the presence of these engagement teams and NYPD-Health co-response teams in Bronx parks with the greatest presence of syringes.”