US lawmakers on Monday were set to introduce a bipartisan $908 billion stimulus proposal aimed at breaking a lengthy deadlock on spending to help the pandemic-ravaged economy.

The measure would pay for aid programs to state and local governments, the unemployed and small businesses and was supported by both Democrats and Republicans, but its chances for passage in the final weeks of President Donald Trump's term remain unclear.

"We're really hopeful this will be the package that will be part of the final agreement that we have to vote on this week," Democratic House representative Josh Gottheimer, a member of the bipartisan group backing the proposal, said in an interview on CNBC.

The bill would follow up on the $2.2 trillion CARES Act rescue package passed in the Covid-19 pandemic's early days, which was credited with keeping the US economy from a more severe downturn even as its major provisions have expired in recent months.

The $908 billion relief proposal backed by a bipartisan group of lawmakers faces uncertain prospects
The $908 billion relief proposal backed by a bipartisan group of lawmakers faces uncertain prospects AFP / MANDEL NGAN

Lawmakers from both parties as well as the Trump administration have been deadlocked for months on passing a follow-up measure, with the sides unable to agree on how much to spend, and what to spend it on.

The $908 billion bill is supported by the bipartisan Problem Solvers Caucus comprised of legislators from both parties, but it remains unclear if it will earn the support of party leaders as well as Trump, who is set to hand power to President-elect Joe Biden in January.

Treasury Secretary Steven Mnuchin last week unveiled a $916 billion proposal, but it attracted little support among Democrats, who control the House of Representatives.

Republican Senate Majority Leader Mitch McConnell most recently suggested passing a measure that excluded two of the most contentious provisions -- liability protections for businesses and aid to state and local governments -- but Democrats also rejected that.

Lawmakers are up against two deadlines: the end of the week, when their session ends, and December 26, when benefit programs paid for by the CARES Act that support millions of unemployed will expire.