US President Barack Obama has arrived back in Washington in a last-ditch effort to avoid the so-called "fiscal cliff", even as key figures in any deal - House Republicans - stayed home.
Cutting short his own Christmas holiday in Hawaii, Obama arrived at the White House shortly before noon on Thursday (1am on Friday Perth time), ignoring questions about the looming financial crisis shouted by reporters as he strode inside.
He has returned to a sharply divided Washington, where the mood has soured on a possible plan to prevent hundreds of billions of dollars in tax hikes from hitting all Americans and deep automatic spending cuts from kicking in beginning January 1.
Politicians have stubbornly refused to compromise, and the Senate's Democratic leader blamed Republicans for the breakdown.
With less than five days before a year-end deadline, Senate Majority Leader Harry Reid said "it looks like" the US economy will hurtle over the fiscal cliff because House Speaker John Boehner and Republican Minority Leader Mitch McConnell were stalling.
Reid said Boehner was running a "dictatorship" in the House by refusing to put to a vote a Senate-passed bill which would prevent taxes from rising on all households making less than $US250,000 ($A242,000) per year.
He also took Boehner to task for keeping his members on holiday instead of returning for a rare holiday week session.
"Without participation of leader McConnell and Speaker Boehner, nothing can happen on the fiscal cliff - and so far they are radio silent," a furious Reid said on the Senate floor.
Obama called Boehner, McConnell, Reid and House Democratic leader Nancy Pelosi late on Wednesday to discuss the way forward, the White House said.
McConnell's office said the senator was "happy to review what the president has in mind, but to date, the Senate Democrat majority has not put forward a plan".
"When they do, members on both sides of the aisle will review the legislation and make decisions on how best to proceed," it added.
Last week, Obama urged Congress to end the deadlock.
The situation has spooked markets, left Americans wondering whether they will pay thousands more in taxes next year, and worried the Pentagon, which fears defence cuts could undermine the military.
Complicating efforts to avoid fiscal disaster, Treasury Secretary Timothy Geithner warned that his department will need to take "extraordinary measures" to keep the US government from defaulting on its liabilities.
Geithner said in a letter to Reid that the nation will reach its statutory $US16.39 trillion debt limit on December 31.
His measures would create some $US200 billion in headroom that under normal conditions could last until the end of February.
With the cliff deadline fast approaching, Obama has pared back his hopes for a year-end, multitrillion-dollar grand bargain that slashes the deficit over a 10-year period.
Instead, he said Congress should approve a stop-gap measure that protects middle-class taxpayers while laying groundwork for further deficit reduction next year.