HARRISBURG — Gov. Tom Wolf threatened Wednesday to veto a fresh piece of spending legislation that Republicans offered as an end to an eight-month budget fight, but that the Democrat criticized as "irresponsible and unbalanced" without a tax increase.

The partisan standoff has left billions of dollars in limbo and the state operating on a $23.4 billion budget, nearly $6 billion less than last year. Public schools are borrowing to stay open while Penn State has threatened to shut down agricultural extension offices across the state.

Meanwhile, the state is funding prisons and Medicaid costs without legislative authority two-thirds of the way through the state government's fiscal year, and a fight already is shaping up over a projected deficit of approximately $2 billion in the fiscal year beginning July 1.

"Despite repeated efforts by my administration to work with Republican leaders to find compromise, including over the last couple days, Republican leaders are once again insistent on passing another irresponsible and unbalanced budget that does not fund our schools or fix the deficit," Wolf said in a statement.

Wolf issued the threat to veto the $6 billion spending bill between a 31-18 vote in the Republican-controlled Senate and a 128-63 vote in the GOP-controlled House. Every Republican and 14 Democrats supported the measure, which could arrive on Wolf's desk Thursday.

Tax-averse Republicans said they were advancing the spending measure as a way to resolve the budget fight before schools close or hospitals and universities resort to mass layoffs to get by without state aid.

"As important as structural deficits are ... it pales in comparison to the decision parents are going to have to make if their schools are closed," Senate Majority Leader Jake Corman, R-Centre, said during floor arguments. "It pales in comparison to the decision that employees are going to have make, are they going to work without pay. That's the real life decision that's going to happen if we do not pass this budget and the governor does not sign it. That's the real world, that's not the halls of this Capitol."

Republicans designed it to be part of a $30 billion package, increasing spending from the state's main bank account by about $870 million, or 3 percent. The Republican plan would deliver half of the public school aid increase, $200 million, or 3.5 percent, that Wolf had initially sought last year.

In the House, Democrats cooperated Wednesday in authorizing about $578 million for five state-subsidized universities — Penn State, Pitt, Temple, Lincoln and the University of Pennsylvania's veterinary school. The money required a two-thirds vote of approval and had been stalled in the House, where Democrats have backed Wolf's opposition to GOP spending plans.

The university funding represented a 5 percent increase. However, Wolf's office said he would veto the legislation.

"We simply do not have the money for these appropriations, and unfortunately, it has become common practice for Harrisburg to refuse to pay the bills it has racked up on the taxpayer's credit card," Wolf's office said.

Going into the fiscal year, Wolf had sought a multibillion-dollar tax increase to resolve a long-term deficit that has damaged Pennsylvania's credit rating and to begin wiping out 2011's budget-balancing funding cuts to public schools.

A bipartisan deal backed by Wolf collapsed just before Christmas after House GOP leaders pulled support. That $30.8 billion spending plan would have required a $1 billion-plus tax increase. Republicans subsequently sent a $30.3 billion plan to Wolf, and he vetoed billions of dollars in subsidies for schools, prisons and Medicaid.

With the current fiscal year nearly over, Wolf is seeking a $2.7 billion tax increase in the coming fiscal year. However, top Republican lawmakers have said they are committed to resolving the deficit without a tax increase.