ST. PAUL — The chairman of the Senate’s judiciary panel warned Monday that if Minnesota lawmakers don’t reform the state’s imperiled sex offender treatment program in their upcoming session, a judge may do it for them.

Judiciary Committee Chairman Ron Latz urged quick action to avoid an embarrassing legal finding that the state is unconstitutionally detaining some former sex offenders who have completed their prison sentences. Other lawmakers raised an even more primal fear: that such a ruling could result in the sudden release of sex offenders whom the state has kept in custody for years out of concern they still represent a threat.

There are currently 690 people in the Minnesota Sex Offender Program, most of them indefinitely committed to treatment in Moose Lake and St. Peter after finishing prison terms. In the program’s 19-year history, only one person has been released from custody, and U.S. Magistrate Judge Arthur Boylan has told state officials to change the program or risk being ordered to do so.

“The court’s not going to wait forever for us to do our job,” said Latz, DFL-St. Louis Park. He said the legislative session that starts at the end of February would likely be legislators’ last chance of avoiding judicial intervention.

The state Senate passed a bill last year that created less restrictive options for people who achieve certain treatment goals, but it never got a vote in the House. In the meantime, the case of one convicted sex offender seeking to be released has recently become tied up in politics.

Democratic Gov. Mark Dayton and his human services commissioner have not opposed the release of Thomas Duvall, a convicted multiple rapist whom a state review panel said meets the criteria to be released. GOP state Rep. Kurt Zellers, who wants to run against Dayton next November, has criticized the governor for that stance. In response, Dayton last week said he would not support any other requests for release until after the Legislature changes the program.

State Sen. Warren Limmer, R-Maple Grove, said lawmakers from both parties would have to try to avoid the political minefield.

“We should make a political truce on this, and get it behind us,” he said.

The number of people in the sex offender program has risen sharply, from 149 in 2000 to the current 690. The Department of Human Services estimates that without legislative or judicial changes, that number would likely reach 995 by 2018. Minnesota is one of 20 states with some form of civil commitment for sex offenders, and also has the lowest incidence of releasing those detainees of any state in the nation.

The one person to be released from the program, in March 2012, moved first to a halfway house and now lives in a supervised group home setting, said Robin Benson, deputy general counsel at the Department of Human Services. He has not committed any other offense, Benson said.

Senators on the Judiciary panel discussed new criminal sentencing guidelines that would keep multiple sex offenders behind bars longer. But Sen. Kathy Sheran, DFL-Mankato, pointed out that wouldn’t solve the more immediate problem of the nearly 700 people now in custody, to whom tougher sentences would not apply.

A task force, led by former state Supreme Court Chief Justice Eric Magnuson, is expected by Dec. 1 to release recommendations for ways to make it easier for some offenders to get released from the program. That’s likely to be the basis for legislative changes.

Sen. Kari Dziedzic, DFL-Minneapolis, said lawmakers have to acknowledge the consequences of not acting.

“There is a chance the federal court could say, ‘You can’t keep them anymore,’ and open the door and let them all out,” Dziedzic said. “I think that’s a long shot, but we don’t know.”