Even before a $1 billion construction bill reached him, Minnesota Gov. Tim Pawlenty vowed Monday to strike the measure down because he was upset about its size and the slate of projects it would finance.

The Republican governor issued his veto warning just as the Democratic-led Legislature took final votes on their marquee legislation of the session. It passed the House 85 to 46, which was followed by a 47-19 vote in the Senate.

Pawlenty has the option of paring it back through line-item vetoes, but he said he had decided to scuttle the bill entirely. Lawmakers have until mid-May to work out an alternative.

“The people of Minnesota expect us to spend their tax dollars frugally and wisely,” Pawlenty wrote in a letter to the bill’s authors. “This bill does neither.”

Lawmakers had finished crafting the borrowing plan early Monday. Its total exceeded Pawlenty’s own proposal by a few hundred million and excluded his priorities, such as $90 million to expand a sex offender treatment facility in Moose Lake and millions more for work on the Minneapolis Veterans Home and the maximum-security prison in Oak Park Heights.

House Majority Leader Tony Sertich, a Democrat, criticized Pawlenty’s last-minute threat, delivered as the governor was returning from a five-day trip to Washington for a mix of political and official business.

“We stand by our product,” Sertich said. “This is typical Pawlenty politics — threaten a veto, veto it and continue with the gridlock. It doesn’t serve unemployed Minnesotans, particularly in the trades.”

Attempts to send the bill back to the committee for more work failed, to the dismay of Republicans.

“We’re jumping off the cliff with a bill that’s going nowhere,” said Senate Minority Leader David Senjem, a Rochester Republican. Senjem wound up voting for the bill.

Leading lawmakers rushed to advance the bill they hoped would get paychecks to idled hard-hat workers around the state and improve critical infrastructure in the process. One-third of the proceeds from a bond sale would pay for science labs, classroom renovations and other building projects on college campuses. Proceeds also would upgrade wastewater treatment plants, clean up landfills and step up flood prevention.

Democratic Rep. Alice Hausman, chairwoman of the House Capital Investment Committee, described the plan as “responsible and focused.” Her counterpart in the Senate, Democrat Keith Langseth, predicted it would support at least 21,000 construction jobs.

Pawlenty and other Republicans seized on projects they considered low-priority items: millions for trail repair, sports complexes, arts buildings and civic center expansions. Pawlenty also scolded lawmakers for including money for snowboarding and snow tubing at a Minneapolis park, which were billed in the legislation as training areas for “Olympic-caliber athletes.”

Rep. Marty Seifert, a Republican candidate for governor, blasted the bill for “spending money we don’t have to buy things we don’t need.”

There were also sizable amounts for local bridge repairs, mass transit projects and zoo exhibits. Less costly but notable was $1.2 million to shore up security at the Capitol complex and $75,000 toward remodeling the official governor’s residence on Summit Avenue.

Architects of the plan defended leaving out money for the sex offender facility and hinted that it could come in another bill later in the year. They said costs are mushrooming for the lockup program, aimed at keeping sex predators confined even after their prison sentences expire. Instead, they ordered a study of the civil commitment program and money needed to support it.

The bonding bill, as its known, was crafted with unusual speed this year. Lawmakers are voting on a negotiated bill less than three weeks into their session, months earlier than usual. The pace is built on hopes of funneling more money into the pipeline ahead of this year’s construction season. An emphasis was placed on picking projects that are well past early planning stages.

“We’re not supposed to have one-man government in this state,” a frustrated Langseth said. “What we put together was a bill we thought would work.”

Pawlenty said he considered his veto “an opportunity to hit the ’reset button.”’

The bill would have minimal effect on the $1.2 billion budget deficit lawmakers are trying to fix because it relies on the sale of long-term state bonds.