Mr Obama said his plan was designed to stop a crisis becoming a catastrophe
President Barack Obama has urged Congress to pass his $800bn (£541bn) stimulus plan, warning that delaying it would worsen a "full-blown crisis".
In his first White House prime-time news conference, Mr Obama said only government could break the vicious cycle crippling the US jobs market.
He said his plan will create up to four million jobs and help lift the economy.
The House of Representatives has already approved the plan and the Senate is due to vote later on Tuesday.
The version approved by the House differs from that being discussed in the Senate, and the two chambers will have to agree on a single final version.
The Senate voted 61-36 on Monday to end its debate, paving the way for a final vote on the Senate's version of the bill on Tuesday.
In his maiden prime-time news conference, Mr Obama stressed that approval of his economic package was extremely urgent, as the present crisis was unlike any other faced by the US for 60 years.
We can't posture and bicker and resort to the same failed ideas that got us in into this mess in the first place
US President Barack Obama
Appealing for a bipartisan approach from lawmakers, Mr Obama said those who opposed parts of his package should remember his administration had inherited the economic crisis, and was trying to lay the foundation for the creation of jobs.
"The federal government is the only entity left with the resources to jolt our economy back to life," he said.
His immediate priority was to stop the downward spiral - to put money in people's pockets, to ease credit and to make sure the economy stopped shrinking, he said.
He said the root of the current crisis had been banks taking "exorbitantly wild risks" with other people's money.
The BBC's Kevin Connolly in Washington says the president was using this performance to appeal directly to the US people over the heads of other politicians.
Foreign affairs issues were also raised at the news conference.
Asked about relations with Iran, President Obama said he was looking for "openings that can be created where we can start sitting across the table face-to-face".
Earlier, the US president gave his first public speech on the plan in Indiana - a state hit hard by the economic crisis.
At the town hall-style meeting in Elkhart, Indiana, Mr Obama conceded that the stimulus plan was "not perfect" but insisted it could help create jobs and "jump-start" the economy.
"I can't tell you with 100% certainty that every single item in this plan will work exactly as we hoped," he said.
"But what I can tell you is... that endless delay and paralysis in Washington, in the face of this crisis, will only bring deepening disaster."
Mr Obama is due to appear in Fort Myers, Florida, on Tuesday, and Peoria, Illinois, on Thursday. Like Elkhart, both are cities that have been badly affected by the economic downturn.
The House and Senate measures are largely similar, but there are differences over how to expand the federal medical programme, Medicaid, and on spending priorities.
While the House bill would give more money to schools, local governments and individual states, the Senate bill devotes more resources to tax cuts.
US lawmakers will have to combine the two bills and have a finished version ready by the president's deadline of 16 February.
New US employment figures were released on Friday showing that nearly 600,000 jobs were lost in January, pushing the unemployment rate to 7.6% - its highest in 17 years.
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