US Senate negotiators have reached agreement on the major components of a $US1.2 trillion ($A1.6 trillion) bipartisan infrastructure bill, clearing the way for a procedural vote to move toward formal debate and passage, lawmakers say.
The agreement, which follows months of talks between Senate Democrats and Republicans, is also backed by US President Joe Biden and expected to gain strong support from lawmakers on both sides of the aisle.
Democratic Senator Kyrsten Sinema and Republican Senator Rob Portman, the two lead Senate negotiators, announced the agreement to reporters in the Capitol.
Details on transit and broadband were still being finalised but lawmakers said legislative text would be completed soon.
"We do expect to move forward this evening. We're excited to have a deal," Sinema said.
"We've got most of the text done, so we'll be releasing it and then we'll update it as we get those last pieces finalised."
Sinema described Biden as "very excited" about the package.
Addressing a concern over funding among Republican lawmakers including Senate Minority Leader Mitch McConnell, Portman said the package is "more than paid for" and added: "We look forward to moving ahead and having a healthy debate."
The procedural vote expected on Wednesday would simply limit debate on whether the Senate should begin considering a bipartisan infrastructure investment bill, thought to be in the range of $US1.2 trillion.
The bipartisan bill, which failed a similar vote last week when major issues remained unresolved, is a key component of Biden's larger domestic policy agenda.
Democrats plan to address the remainder with a sweeping $US3.5 trillion reconciliation package that Republicans have vowed to oppose.
Four other Republican negotiators joined Portman, including Senator Lisa Murkowski, who said the agreement showed Republicans and Democrats in the sharply divided US Congress "can come together over really hard stuff to negotiate in good faith to broker an agreement".
The agreement includes $US110 billion for roads, $US65 billion to expand broadband internet access and $US47 billion for environmental resiliency, the lawmakers said.
Earlier, Senate Majority Leader Chuck Schumer said a procedural vote on a bipartisan bill was possible as soon as Wednesday night.
"Senators continue to make good progress," Democrat Schumer said in a speech on the Senate floor.
Before the announcement, Murkowski told reporters: "I think that there is a strong, solid number of folks on both sides of the aisle that want to get on to an infrastructure package".
Democrats hope to pass this month or early next month whatever measure is agreed upon in the bipartisan negotiations.
Australian Associated Press