NEW YORK — Correction officials on Friday encouraged the city's jail watchdog board to approve a proposed rule change to allow for the creation of a 250-bed restrictive housing unit at Rikers Island for the 2.2 percent of inmates they say are responsible for the vast majority of violence.

Speaking at a public hearing before the oversight board votes on the $14.8 million proposal next month, Commissioner Joseph Ponte said the unit will allow jail officials to finally control a system racked by inmate-on-inmate violence so that much needed reforms can be instituted.

"We don't get all of this violence by accident," Ponte said, referring to current housing setups and a backlog of inmates who owe time in solitary confinement but are in general population because there aren't enough beds.

James Dzurenda, Ponte's first deputy commissioner, said violence at Rikers was fueled by an influx of scalpels that go undetected by metal detectors when wrapped in electrical tape and hidden inside body cavities. He said visitors pass them along to inmates — and that's why contact visits in the new unit would be eliminated.

"That's a scary thing," he said of the practice.

Jail officials described the unit as one in which inmates can earn rewards with good behavior, eventually working their way back to the general population after receiving therapy and socialization programs.

But some board members, inmate advocates and former city health officials raised doubts about the unit, which would lock the inmates in their cells for up to 17 hours daily instead of eight, prohibit contact visits and end their access to the law library, among other restrictions.

Daniel Selling, the recently retired former head of jail mental health services, told the board that previous special housing units for difficult inmates had been pitched as rehabilitative units where services would be provided but had nevertheless turned into highly restrictive units void of therapeutic services.

"According to the policy, no more than half of the inmates could be out of their cell during any shift and inmates will be afforded a minimum of seven hours out of cell time daily," he testified. "This will never be adhered to. It is aspirational at best but not possible."

Selling also noted that no officials from the Department of Health — who are responsible for inmates' mental and physical care — were present at the public hearing.

In a statement, Health Commissioner Mary Bassett said the seriously mentally ill and adolescents would be excluded from the unit, and she and jail officials believed they'll "be housed in more appropriate settings where they can get the treatment they need."

Asked by a board member why proposed reforms to reduce the use of solitary confinement — including eliminating time-owed in 23-hour confinement from previous jail stints — were dependent on the approval of the so-called enhanced supervision housing, Ponte said it was a key piece of inmate management.

The proposal doesn't include any requirements for guards assigned to it to receive special training.

Ponte told reporters after his testimony that guards assigned to the unit would receive more mental health first-aid and other training.

"We all agree our jails need to be safe," he said.

When asked whether Ponte had discussed the unit's creation with federal prosecutors who sued the city Thursday to speed up the pace of reforms at Rikers, he said he hadn't specifically talked with them about the plan.

The union representing 9,000 correction officers submitted testimony supporting the housing unit but insisted steady officers be assigned instead of rotating guards unfamiliar with the population.