(Bloomberg) -- The U.S. Senate on Saturday begins working through a round of proposed amendments to a $550 billion infrastructure package in one last drive to finalize the massive public works plan.

Senators have more procedural votes before moving forward, but the legislation appears to be on track to pass as soon as this weekend after weeks of negotiations between the White House and Republican and Democratic lawmakers.

President Joe Biden on Friday urged the Senate to complete its work on the legislation, which would be the biggest investment in the nation’s infrastructure in decades and is a key element of his economic agenda.

“It’s a bill that would end years of gridlock in Washington and create millions of good-paying jobs, put America on a new path to win the race for the economy in the 21st century,” Biden said at the White House.

Senate Majority Leader Chuck Schumer plans to pivot quickly after the infrastructure vote to a budget resolution that will set the stage for a much broader $3.5 trillion package of social spending and taxes that Democrats can muscle through without any Republican votes.

The Senate will have to confront one unresolved fight before passing the infrastructure bill: two dueling amendments to modify a provision of the bill dealing with reporting requirements for cryptocurrency transactions and tax collection. The bipartisan group that drew up the legislation was counting on the extra tax revenue generated to help pay for some of the bill’s costs.

Senate Finance Chairman Ron Wyden, a progressive Democrat, teamed up with conservative Republicans Pat Toomey and Cynthia Lummis in working with the cryptocurrency industry to draft changes to narrow who would be affected by the reporting requirements. It would exclude entities including miners, software designers and protocol developers from the groups that need to report data to the Internal Revenue Service.

But Senators Rob Portman, a Republican, and Democrats Mark Warner and Kyrsten Sinema -- three key players in negotiating the infrastructure legislation -- proposed an 11th-hour alternative endorsed by the White House. It would target some software companies and cryptocurrency miners.

The dispute risks causing a rift between the Biden administration and Wyden, who will be the most important figure in making sure the president’s tax agenda can clear the Senate later this year.

White House press secretary Jen Psaki on Friday said the administration is “grateful” for Wyden’s leadership on crypto issues, but reiterated that it prefers the alternative plan.

“I would just go back to the overarching objective here which is reducing tax evasion in the cryptocurrency market, and we feel that the compromise sponsored by Senators Warner, Portman, and Sinema is a good option,” she said.

The Blockchain Association, a trade group for the industry, mounted a last-minute pressure campaign in favor of the Wyden-Toomey-Lummis version. Wyden said they were making the case to colleagues that their version makes it “very hard for tax cheats, without discouraging innovation.”

The crypto amendments, which are mutually exclusive, could both be considered again on Saturday, but it’s unclear if they will each get a vote. It’s also not certain what happens if they both pass. One possibility is that they would be added to the bill to be sent over to the House, with differences resolved in that chamber.

The infrastructure bill includes $110 billion in new spending for roads and bridges, $73 billion for electric grid upgrades, $66 billion for rail and Amtrak, and $65 billion for broadband expansion. It also provides $55 billion for clean drinking water and $39 billion for transit.

The legislation still faces challenges in the House, where Democrats can only afford three defectors if Republicans vote in unison against the bill. House Democrats are divided over whether the package spends enough and many Republicans oppose the bill.

Speaker Nancy Pelosi reaffirmed Friday that the House won’t take up the infrastructure legislation until the Senate also passes the more sweeping budget package. That linkage has been a central demand of progressive Democrats in the House, though moderates have been urged on Pelosi not to hold on to the infrastructure bill. The House is currently on a recess until Sept. 20.

“We are not going forward with leaving people behind,” Pelosi said at a news conference.

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