Gov. Corbett's administration - along with city and state officials - is working to assemble a funding package that could pump as much as $100 million more into the coffers of the Philadelphia School District, according to sources with knowledge of the high-level talks.

But the money, which could include federal funds the state would send to the cash-strapped district, might come with hefty strings attached, they said.

The additional aid would be contingent on the district's ability to obtain major concessions from the Philadelphia Federation of Teachers, including requiring teachers to work a longer school day and contribute to their health-care coverage, sources said.

State Sen. Anthony Hardy Williams (D., Phila.) confirmed the general outline of the talks in Harrisburg.

"We're talking about addressing the Philadelphia problem," he said.

Williams said a figure of $100 million had been mentioned, but he said details of a plan were still being hammered out.

He denied that union concessions would be required as part of the deal.

The talks come as the district scrambles to fill a $304 million shortfall by July 1 and avert the announced layoffs of 3,783 employees at schools and 76 at the district's headquarters and regional offices.

To plug the shortfall, Philadelphia Superintendent William R. Hite Jr. has asked for $60 million more from the city and $120 million from the state. He also is asking for $133 million from the unions, mostly from the PFT.

Mayor Nutter and Hite traveled to Harrisburg again Tuesday to seek support for the schools. Mark McDonald, Nutter's spokesman, declined to comment on the proposed package.

"The mayor has had numerous discussions with city and state stakeholders in recent weeks and days. They have looked at and analyzed a variety of ideas and scenarios," McDonald wrote in an e-mail.

"The most important point right now is that all parties are talking about the funding issue and taking it seriously."

Senate Majority Leader Dominic Pileggi (R., Delaware) said the legislature was still trying to decide how much to send to financially strained school districts, including Philadelphia.

"It is very clear at this point that there are a limited amount of dollars to go around the state for that purpose," Pileggi said.

He said Republicans who control the Senate were considering a distressed-schools package similar to the one in this year's state budget, but he would not say how much money would be set aside for it.

The state budget now provides roughly $50 million in special aid to 16 school districts considered financially distressed or receiving loans for financial recovery. The roster includes the Upper Darby and Chester Upland School Districts, but not Philadelphia.

Asked whether his Republican colleagues believed Philadelphia should get the $120 million it has asked for or whether a smaller amount was more realistic, Pileggi said: "I think a smaller figure is more realistic. There is a great deal of concern about our school districts, largely urban, that are facing difficult fiscal situations . . . so we need to look at the entire state, not just Philadelphia."

He added: "Philadelphia is the largest school district by far . . . but the problems in some of the smaller districts are [as] real and pressing to the people who live there."

Senate Appropriations Chairman Jake Corman (R., Centre) said he would be willing to consider a freeze in a planned business-tax phaseout - for the so-called capital stock and franchise tax - to free dollars that could be redirected to public schools.

"Whether we do it or not remains to be seen," said Corman, who said he would consider rolling the tax back to 2012 levels. "Is that phaseout more important than education dollars? Higher education dollars? . . . Economic development dollars? That's what you are weighing."

Williams and others said extending Philadelphia's extra one-cent sales tax and diverting part of the money to the schools is one component of a possible scenario to give the district more financial stability. The tax is scheduled to expire June 30, 2014.

McDonald would not comment on a possible sales-tax extension.

Philadelphia officials also have appealed to U.S. Rep. Bob Brady (D., Phila.) for federal funds for city schools.

Brady "is using every effort he can expend to get every dollar he can to the Philadelphia schools, especially in light of what's been going on recently," his chief of staff, Stan White, said Tuesday.

"He has a commitment from the governor's office that any funds he can find or savings to the commonwealth will go the Philadelphia School District."

Corbett aides said they have discussed several possible plans with top city officials, but did not provide any details.

Williams said lawmakers want the PFT to show its willingness to help the district resolve its financial crisis, but denied that any new state aid would be linked to specific concessions. The contract expires Aug. 31. "There's not a quid pro quo," he said.

Hite said Tuesday there would be no resolution with the unions before the state passes a budget.

"I'm not anticipating that negotiations will be complete before the end of the session. [Legislators] understand negotiations as well, and they understand it's a process. While it may not be enough, it's where we are currently."

Inquirer staff writer Troy Graham contributed to this article.