Gov. Chris Christie’s administration came under heavy criticism from legislators last month at hearings on New Jersey’s privately run halfway houses, which handle thousands of inmates each year. On Wednesday, Mr. Christie fired back, saying he would significantly weaken a measure approved by the legislators to increase their oversight of the system.

It was the second time Mr. Christie moved to weaken new regulations for halfway houses.

The Democratic-controlled Legislature approved a bill in June that required the state auditor to conduct reviews of major corrections contracts with private operators, including those with a halfway house company that dominates the system and has close ties to Mr. Christie.

But the governor, a Republican, said Wednesday that he would sign the law only if all existing contracts, including those with halfway house operators, were exempted from the audits.

He described the provision, freeing those contracts and their renewals from review, in a footnote toward the end of a four-page statement on the bill.