This would be only the second time the state has borrowed money from its pension fund, and it would involve much more money than the previous time, which occurred in the aftermath of the Sept. 11 terrorist attacks. New York State faces a $9.2 billion deficit this fiscal year, which began on April 1, and the budget is already more than two months late. The governor and legislative leaders are under pressure to make structural changes that will bring new discipline to state spending, but few expect them to do so.

Instead, they are expected to rely heavily on borrowing, tax or fee increases and an array of one-time maneuvers, like tapping the coffers of public authorities.

The governor and Comptroller Thomas P. DiNapoli back borrowing against the pension system, and a tentative agreement to do so was reached after negotiations on Thursday among key lawmakers and the governor’s representatives. The plan excludes New York City, which has its own pension system.

The initial plan in the governor’s budget called for the borrowing of up to $9 billion over the next six years.

Under the agreed-upon plan, the state would be authorized to borrow $1.5 billion to $2 billion over the next three years, according to forecasts provided by the governor’s office and the Senate. Municipalities would be allowed to borrow nearly $4 billion, according to a Senate estimate.

Senator Diane J. Savino, a Staten Island Democrat who negotiated the agreement for the Senate, said she pushed for a limit.

“There’s a question as to whether or not we should do this,” she said, adding, “I didn’t want to leave it open-ended, because six years is too long. The temptation is too great to do it over and over again.”