ATLANTA - The frenzied final day of the state's 40-day legislative term began Friday with the threat of a special session hanging over the hubbub of activity at the state Capitol.

Legislators were set to debate a slew of bills, ranging from changes to the state's beleaguered PeachCare system to a measure that would loosen class size caps in high schools.

But all eyes were on the state budget after Gov. Sonny Perdue vetoed the midyear spending plan late Thursday. Unless the House and Senate gather the two-thirds vote needed to override Perdue's veto, lawmakers will have to start from scratch on the $700 million supplemental spending plan. That would probably involve bringing the weary state Legislature back to Atlanta for a special session at a cost of roughly $45,000 a day, according to the state Senate Fiscal Office.

House and Senate leaders also have yet to strike a deal over next year's $20.2 billion budget. The budget is the only action the state Legislature is required by law to complete each year.

The two sides have yet to hash out dueling proposals to tighten the state's PeachCare system, the cash-strapped health insurance program for poor children.

Also up for consideration is a Senate measure that could give developers the power to tax residents for infrastructure improvements. The measure was scheduled to be debated on the House floor three times this week, but each time it was delayed by supporters.

There's a chance the House could vote again on a measure that would allow the residents of Dunwoody to decide in a referendum whether they wish to form their own city. The bill was defeated in the House by a 81-71 vote, but lawmakers narrowly voted to reconsider the move. It was then tabled, allowing its sponsor to bring it up for consideration again.

Among the other bills pending in the House is a proposal to create an umbilical blood cord bank for stem cell research and another that would give private school vouchers to students with disabilities.

The chambers will consider dozens of other measures during the marathon day, which could last well into the night. Yet there's a chance that the legislative work may not be done for the year once the session is gaveled to an end.

Perdue's veto of the spending plan could force him to call lawmakers back to Atlanta for a special session if an accord is not reached.

"I don't want that." Perdue said Thursday night. "I've told them I don't want that. I don't think they want that. But we have a lot of work with one day left."