BOISE, Idaho (AP) - The growth of Idaho's budget surplus in May places renewed pressure on lawmakers to address property tax relief, possibly in a special legislative session, Gov. Jim Risch says.

"That money is there," Risch said Tuesday. "And people are saying to me, 'I don't understand this. I'm getting these tax increase bills where I have to pay all this additional money and you guys are sitting on $168 million dollars? What's wrong with this picture?"'

Idaho had a higher-than-expected $33.3 million increase in state revenue last month, for a running total projected surplus of $168.5 million.

Adding about $50 million unspent from last session, the Legislature will have roughly $219 million in its coffers with one more month left before the fiscal year ends on June 30.

Touting the state's sunny fiscal outlook, Risch has called for shifting Idaho's school maintenance costs from property taxes to the sales tax.

The move, Risch said, would ease the burden on property owners whose tax rates are climbing as property values soar.

He again pledged support for a special session on a property tax plan.

"The Legislature spent a long time talking about this and spent a long time studying," Risch said. "And I hate to see that go to waste. Come January you are going to have a new Legislature."

In May, individual income tax collections were up by a projected $26.2 million. Corporate income taxes rose about $3.1 million and sales taxes were up $4 million.

April had a record revenue increase of $110.1 million.

But some lawmakers said the state should not rush into a special session before analysts can determine if surpluses will continue.

"It does make sense to wait until the end of the fiscal year to see what the final numbers are," Sen. Shawn Keough, R-Sandpoint, told The Coeur d'Alene Press. "It also makes sense to hear from professionals whether it is ongoing."

Last session, Keough sponsored several bills aimed at reducing property taxes. She said some senators appear ready to transfer the cost of public school maintenance and operation from property taxes, but "the Democrats are pretty dug in."

Sen. John Goedde, R-Coeur d'Alene, agreed it was premature to spend the $219 million before all state revenue figures are calculated at the end of the fiscal year.

"That doesn't mean we don't have the potential to use that," he said.

Goedde said another option is to relieve taxpayers in community college districts.

Kootenai, Jerome and Twin Falls counties are the only counties that support community colleges through property taxes. In 2005, $5.8 million in property taxes from Kootenai County went to fund North Idaho College.