BOSTON — As a judge considers forcing the state to pay for a convicted murderer's sex-change operation, Sen. Bruce Tarr, R-Gloucester, has filed legislation that would bar taxpayers from footing the bill.

"I want to put into the law something that there is fairly widespread agreement on," Tarr said yesterday. "That this is a procedure that shouldn't be paid for, especially when the budget is tight and the Department of Corrections is strained to perform basic functions."

If passed, Tarr's bill would prohibit any use of public money to pay for "sex reassignment surgery" for anyone held at any of the state's jails or prisons.

The state couldn't pay for hormone replacement therapy for any person in jail or prison, unless a doctor approved the therapy for something other than a sex-change operation. And it couldn't pay for laser hair removal treatment.

Tarr filed his bill as U.S. District Court Judge Mark Wolfe considers requiring the state to pay for a sex-change operation for Michelle Kosilek. Born Robert, Kosilek has sued the state, saying the procedure is medically necessary.

Tarr said the procedure is not necessary, and it's unfair to have the state pay for the surgery for a prisoner when the state doesn't for its poorest citizens.

"It's something we don't even allow to be paid for with Medicaid," Tarr said.

Tarr's bill does not prohibit the state from paying for other elective procedures. He said he was responding to a recent controversy, and would consider filing additional legislation as the need arises.

Diane Wiffin, a Department of Correction spokeswoman, declined to comment on the legislation because the subject is being litigated.

Sen. Steven Baddour, D-Methuen, supports the measure. Sen. Susan Tucker, D-Andover, could not be reached for this story. Tucker did sign on to a letter circulated earlier this month by Sen. Scott Brown, D-Wrentham, that would instruct Harold Clarke, the state correction commissioner, not to approve paying for the surgery.

The bill also is backed by Essex County Sheriff Frank Cousins.

"He doesn't feel that is an appropriate use of taxpayer dollars," said Paul Fleming, a spokesman.

There are no Essex County prisoners requesting a sex change, Fleming said.

Robert Kosilek was sentenced to life in prison for murdering his wife, Cheryl, in 1990. In 1993, Kosilek changed his name to Michelle and began living as a woman while incarcerated in the all-male Norfolk prison. State correction officials have balked at paying for the operation, saying it would make her a target for sexual assault behind bars.

Kosilek, 58, lost a 2002 lawsuit claiming the state's decision not to pay for the expensive surgery violated her constitutional rights against cruel and unusual punishment.

In 2005, Kosilek sued again, saying hormone treatments to alter her male characteristics were not enough to relieve severe depression. She has twice tried to commit suicide.

Judge Wolfe is deciding if the operation is medically necessary. Clarke, the state correction commissioner, said he would consider reversing the department's long-standing opposition to paying for the surgery after being ordered to appear before Wolfe on April 1.

Legal experts have questioned whether the Legislature can step in while the case is being decided.

If his bill becomes law before Wolfe rules, Tarr said he's unclear if it would prevent the state from complying with the judge's order and paying for the sex change. He said he believes it would give Clarke support in denying Kosilek and future prisoners' requests.