PHOENIX — Republican legislators are focusing possible budget cuts for K-12 schools on building expenses, not dollars for teacher pay or other classroom-related expenses, a key lawmaker said Monday.

With the state’s tax collections taking a hit from the economic slump, legislators are trying to erase a projected $2 billion revenue shortfall in the $10 billion budget being drafted for the fiscal year that begins July 1. Democratic Gov. Janet Napolitano has vowed to protect K-12 school funding, but education groups have expressed uneasiness about the possibility of legislators seeking cuts in public school funding programs not mandated by voters.

House Majority Leader Tom Boone said possible savings might come in both construction of new schools and upkeep of existing schools.

However, majority Republicans are putting a high priority on protecting recent increases in funding directly related to instruction, said Boone, a Peoria Republican who is among 15 GOP lawmakers meeting on the budget behind closed doors.

“There is going to be a lot of desire to ... avoid any kind of significant cuts of any kind, especially to classrooms and teachers for K-12,” Boone said.

Boone’s comments could indicate fellow lawmakers may not adopt such options as eliminating recent funding increases approved by the Legislature for teacher pay and all-day kindergarten. The latter was a Napolitano initiative.

Funding for all-day kindergarten “now is part of the operating budget that would be a classroom, in my opinion, reduction, if that were left out,” Boone said.

On the other hand, lawmakers suspended a $43 million payment for school building upkeep when they cut the 2007-2008 budget and likely will do the same in the next budget as well, Boone said.

And student enrollment growth is down, opening the door for the state to postpone proposed spending on building new schools, he said. “Those are the kinds of things that would be looked at in K-12.”

However, Napolitano’s proposal for borrowing to cover the school construction costs “is still on the table,” Boone said. “Absolutely, I don’t believe we can get out of a budget solution without some capital financing for schools.”

Various state funding streams for K-12 schools add up to more than $4 billion. Voter approvals mean most of it’s protected from possible cuts, and Boone said lawmakers are unlikely to try to invoke an interpretation on the extent of those protections that would be more limited than has been used in the past.