A former state senator, Guy Velella, whose early release on a one-year bribery sentence has been deemed improper by the commission that set him free, challenged the city’s authority to send him back to jail on Rikers Island.

Meeting yesterday’s deadline set by the newly reconstituted Local Conditional Release Commission to explain why he should remain free, Velella’s attorney, Charles Stillman, said his client had already been granted his freedom and made clear he was not reapplying for release, which the board has suggested it would reject.

Mr. Stillman would like the matter to be resolved through the courts, not the commission.

“We want to get this matter to a judge so the courts can decide,” Mr. Stillman said. “The commission doesn’t have the power to revisit what has already been decided.”

A commission spokesman, Jerrold Alpern, would not comment, except to say the commission will review applications on Friday from individuals released by the former board.

The city’s law department, which counsels the commission, has said the board can return Velella to jail if it believes he was released by the former chief commissioner Raul Russi without following procedure, which would include summarily deciding on a case without the requisite three person quorum.

The issue has brought the once little-known board under scrutiny. Yesterday, the chair of the state’s Committee on Correction, Assemblyman Jeffrion L. Aubry from Queens, convened the first of several hearings on the future of the commission, which was established in 1989 to reduce overcrowding in the criminal justice system.

Mr. Aubry said the commission lacks accountability, uniform standards, and criteria for granting early releases and fails to follow lawful procedures.

Mayor Bloomberg favors abolishing the commission, whose mandate expires next September unless re-enacted by state legislators.

Speaking at the hearing today, the mayor’s criminal justice coordinator, John Feinblatt, said the average daily prisoner population in the city is now fewer than 14,000, down 36% from its peak in 1992.

Currently, each county is required to have a commission. One potential alternative may allow each county to “opt in” to the system if they feel it would relieve swells in the prison population, Mr. Aubry said.

Proponents of the commission say the controversy should highlight the original purpose of the board, which was to reduce the prison population by getting alternatives to incarceration for nonviolent offenders.

But in recent years, the commission has rarely exercised its power. Since 1999, more than 32,000 prisoners have applied to the commission, according to a recent report by the city’s Department of Inspections. Since then, only 13 people have been released, including Velella and his two co-defendants, Manny Gonzalez and Hector Del Toro.

The release sparked charges that the veteran state senator from the Bronx used his political clout to garner special attention form the former commissioners, who resigned under pressure from the mayor.

Velella pleaded guilty in May to one count of bribery and was sentenced to one year in jail. He was released after serving less than three months.