Nearing decision time, senators were struggling to wrap up work on the bipartisan infrastructure plan despite hopes to expedite consideration and voting on the nearly $1tn proposal.

The package had appeared on track for eventual Senate passage, a rare accord between Republicans and Democrats joining on a shared priority that also is essential to Joe Biden’s agenda.

But senators hit new problems late Thursday as they worked late into the night on amendments. A procedural vote was set for Saturday.

“We’ve worked long, hard and collaboratively, to finish this important bipartisan bill,” said Senate majority leader Chuck Schumer, just before midnight. In announcing Saturday’s schedule, he said: “We very much want to finish.”

Called the Infrastructure Investment and Jobs Act, the thick bill is a first part of Biden’s infrastructure agenda, and would inject billions of new spending on roads, bridges, waterworks, broadband and other projects to virtually every corner of the nation.

If approved by the Senate, it would next go to the House.

The US president has repeatedly said he wants Congress to pass the bipartisan infrastructure bill as quickly as possible.

Biden has described the bill – which would provide $550bn in new federal funds for roads, bridges and other physical infrastructure projects – as “the most significant long-term investment in our infrastructure and competitiveness in nearly a century”.

“This deal signals to the world that our democracy can function, deliver, and do big things,” Biden said in a statement last week.

“As we did with the transcontinental railroad and the interstate highway, we will once again transform America and propel us into the future.”

Biden acknowledged that Democrats did not get everything they wanted in the bill, but he added: “[T]he bottom line is … the Bipartisan Infrastructure Deal is a blue-collar blueprint to rebuild America that will help make our historic economic recovery a historic long-term boom.”

Thursday’s late-night session stalled out as new debates emerged over proposed amendments to change the 2,700-page package.

Senators have processed nearly two dozen amendments, so far, and none has substantially changed the framework of the public works package. With more than a dozen amendments still to go, senators struggled to reach agreements.

One of the amendments generating the most attention Thursday involved cryptocurrency.

The bill would raise an estimated $28bn over 10 years by updating Internal Revenue Service reporting requirements for cryptocurrency brokers, just as stockbrokers report their customers’ sales to the IRS.

Senator Pat Toomey, Republican of Pennsylvania, and others are concerned that crypto miners, software developers and others would be subject to the new IRS reporting requirement. Toomey led efforts to narrow the definition of who must file the reporting forms to the IRS.

“If we were not to adopt this amendment, then we could be doing a lot of damage,” Toomey said. “We could have a very chilling effect on the development of this technology, and that’s what I am most concerned about.”

A top Republican negotiator, Senator Rob Portman of Ohio, who had written the provision, tweeted that he agreed with the amendment sponsors that more can be done to clarify the intent of the provision and the Senate should vote on their amendment.

But that vote has yet to occur and the White House weighed in late Thursday, suggesting it favored a different approach from Portman and other senators.

White House deputy press secretary Andrew Bates said the compromise amendment “would reduce tax evasion in the cryptocurrency market.”

He said the administration believes “this provision will strengthen tax compliance in this emerging area of finance and ensure that high income taxpayers are contributing what they owe under the law.”

The Senate came to a standstill for nearly two hours late into the night as senators privately debated next steps.

The bill’s top Democratic negotiator, Senator Kyrsten Sinema of Arizona, said, “While we were unable to agree on additional amendments today, I do also look forward to us reconvening together on Saturday and proceeding under regular order to finish what will be a historic piece of legislation – both in its bipartisan nature and the impact it will have in our country.”

Overall, the infrastructure package calls for $550bn in new spending over five years above projected federal levels for a nearly $1tn expenditure, what could be one of the more substantial investments in the nation’s roads, bridges, waterworks, broadband and the electric grid in years.

A much anticipated analysis of the bill from the Congressional Budget Office concluded that the legislation would increase deficits by about $256bn over the next decade.

If senators wrap up work on the bipartisan bill, they will turn to the much more partisan undertaking on the next phase of Biden’s agenda: a $3.5tn proposal for what the White House calls human infrastructure – childcare support, home health care, education and other expenditures that are Democratic priorities that Republicans have pledged to reject. Debate will extend into the fall.

Schumer wants the Senate to pass both pieces of legislation before senators depart for an August recess.