Mayor Bill de Blasio defended his “sugar-coated” tour of Rikers Island in a finger-wagging lecture to the press Tuesday — insisting he didn’t need to talk to the inmates or guards there because he already knows everything he needs to about the troubled jail.

During a remote press conference, the second-term mayor bristled when The Post asked him about his decision not to speak to any detainees or rank-and-file correction officers while visiting the disastrous lock-up Monday and then claiming that wasn’t his “mission.”

De Blasio sniffed that many journalists can’t understand his actions because they simply aren’t as knowledgeable about the “issues” at the jail as he is.

It was the mayor’s first visit to Rikers in four years.

“The bottom line is this: For a lot of you, I think, some of the challenges at Rikers may be new, and I respect that. For me, they’re not new,” de Blasio said.

“I’ve been dealing with these issues. I’ve spent a lot of time understanding those problems over the years, I have talked to inmates, talked to folks who were in Rikers as inmates, have talked to officers. I have a pretty strong understanding of the extent of the problems.

“Those aren’t new problems; those are horrible problems that have existed for years,” de Blasio said. “I don’t need to be reminded of something I already know.”

The mayor made a hastily announced, 90-minute visit to Rikers Island on Monday afternoon — after widespread calls for him to see the squalid, out-of-control conditions at the jail with his own eyes. There have been 11 deaths there so this year, just part of a cascading crisis at the facility.

But the mayor didn’t speak to anyone in custody or a rank-and-file correction officer — or even see a cell that houses a detainee — during his sanitized tour.

“They gave him a watered-down, sugar-coated tour today,” fumed Benny Boscio, the head of the Correction Officers’ Benevolent Association, shortly after the mayoral visit.

“He did not go see any housing areas where inmates are housed, they cleared out the area. You could smell the paint, they’d just painted,” the union chief said.

De Blasio repeatedly told reporters Monday after his visit that it wasn’t his “mission” to speak to inmates or guards.

“I did not, and I want to be very straightforward about that. My mission today was to talk about the work being done, what is needed next, to ask the experts, ‘What is the additional steps, what investments we have to make quickly and urgently,’ ” the mayor said.

Asked again later on NY1 why he didn’t speak to detainees or correction officers, de Blasio sounded like a broken record, repeating that wasn’t within the scope of his visit’s purpose.

“That wasn’t the mission today,” de Blasio said. “The mission today was to figure out the things that we are doing right now, the things we have to do right now, the things we have to add right now to address the situation.

“I have a very sharp, clear understanding of a lot of the problems, I really do. And they’re not new problems.”

Boscio said Tuesday that he has a “serious problem” with de Blasio, who is white, claiming he is familiar with the mostly non-white jail staff’s “suffering.

“It’s tough to confront the suffering you have caused, Mr. Mayor, but we will keep fighting every single day for the men and women you continue to ignore,” the union chief said in a statement. “We call on all elected officials to denounce the mayor’s marginalization of our essential workers.”

City Councilman Keith Powers, who toured the lockup Tuesday for three hours with two fellow Democratic lawmakers, said it would have been “extremely helpful” if de Blasio had actually spoken with detainees and workers at Rikers.

“Seeing it helps, but talking to the folks is really important to see what’s happening there,” Powers told The Post.

“I think it would be extremely helpful for him to talk to people and hear about the conditions,” he added of the Dem mayor. “It’s a critical part of any trip.”

Powers, chairman of the council’s Public Safety Committee, said conditions had improved since he previously observed the jail complex last week.

“It wasn’t like last week at all,” he said, noting that the intake cells were “far less crowded” and that staff was in “the early stages of resolving” other issues, too, including a lack of manpower and the living conditions.

“It almost looks back to normal.”

The politicians’ visits came as the troubles at Rikers Island, which is currently home to about 5,500 detainees, escalated in recent weeks.

Along with jail mayhem, a top city Department of Correction worker revealed that about 20 percent of Rikers’ staff stayed home on a recent Tuesday — a snapshot of the chronic absenteeism that prompted the de Blasio administration to sue a correction officers union for allegedly encouraging and enabling guards to not come to work.

The mayor has announced other measures aimed at getting the jail under control, too, including punishing absentee correction officers and shifting 100 NYPD cops into courts to allow guards to work on Rikers.

But those moves weren’t enough to put an end to the crisis.

The federal monitor overseeing Rikers Island warned Friday that the chaotic jail system is in a “state of emergency,” declaring that outside help is needed to overcome “mismanagement” and “prevalent” failings. Judge Laura Swain in turn ordered City Hall and the monitor to meet on the recommendations.

On Tuesday, the federal monitor and the city filed a joint stipulation in Manhattan federal court, saying they will agree to a number of security recommendations outlined by the monitor in September.

The city will and the monitor will have until Oct. 14 to decide if Rikers needs an “external Security Operations Manager” for the troubled lockup, the letter filed Tuesday states.

Additional reporting by Ben Feuerherd