ST. PAUL — Minnesota’s Republican Legislature on Monday started piecing together a budget offer to send to Gov. Mark Dayton, a package that makes clear GOP lawmakers aren’t backing down from the Democratic governor’s veto threats.

The Legislature has just three weeks to strike a deal with Dayton on a two-year budget before adjourning. As the House and Senate’s proposal for a nearly $45 billion spending package started to materialize, it was clear that agreement wouldn’t come easily.

A bill to fund environmental agencies would delay the launch of Dayton’s marquee water quality initiative requiring buffer strips between cropland and public waterways from this fall until 2019 —a measure Dayton has promised to veto. He’s also objected to abolishing MNsure in favor of moving the state to the federal exchange, though he stopped short of threatening a veto of the measure that the Legislature included in its health care funding bill.

Those disagreements will likely be worked out privately, in meetings between legislative leaders and Dayton that Senate Majority Leader Paul Gazelka said he hoped would start later this week. Gazelka said legislative leaders are aiming to have the remainder of their budget proposal ready for the governor by Monday evening.

Republicans’ surprise takeover of the Senate in November and the GOP’s bolstered has Dayton outnumbered in negotiating the budget. He’s also acknowledged that he’ll need to cede some ground, trying to lower expectations — specifically referencing Republican-backed legislation that would stop cities from raising their own minimum wages or implementing sick leave policies.

“Look at the results of the election,” he said on Minnesota Public Radio News. “If they gave me a DFL Legislature, it’d be a lot easier.”

But Dayton has repeatedly vowed to veto any bill that delays or changes the buffer legislation, saying any changes should wait until after the stronger environmental protections go live in November. Republicans are pressing ahead.

Rep. Dan Fabian said a delay is necessary, citing uproar from farmers who are confused about the regulations and which governmental agencies are enforcing them.

“When the timelines come and they’re out of compliance, what happens then?” said Fabian, a top lawmaker on agricultural issues. “The reality is this just isn’t working. Why is so much of rural Minnesota up in arms about this?”