President Barack Obama was Monday to take his case for a huge economic rescue plan directly to the US public, warning of a "catastrophe" without urgent action, as a pivotal vote loomed in the Senate.

Confronting the biggest challenge of his new presidency, Obama was returning to barnstorming campaign mode with a "town hall" meeting in rust-belt Indiana before his first White House news conference at the prime time of 8:00 pm (0100 GMT).

The president Saturday welcomed signs of a tentative deal by lawmakers on his stimulus plan as the Senate held a rare weekend session, following news that the US economy shed a staggering 598,000 jobs in January.

"Because if we don''t move swiftly to put this plan in motion, our economic crisis could become a national catastrophe," Obama said.

His Indiana visit, to be followed by a trip Tuesday to Florida, underscored Obama''s determination to drum up support in the country at large for a stimulus package that looks set to top 800 billion dollars.

The Democratic-led Senate was Monday expected to decide on a key procedural motion to override Republican blocking tactics and put the package to a full vote, possibly Tuesday.