"Obama believes we cannot wait until he becomes president to give workers the tax relief they need," according to a policy paper.

Obama, a senator from Illinois with Hawai'i ties, called on the government to make available a $250 tax credit to 150 million workers to offset the payroll tax paid on the first $8,100 of earnings. He urged a further $250 tax credit per worker if employment declines three months in a row.

He would also bump up Social Security payments to seniors who would not benefit from the credit based on income with a one-time $250 payment, with another $250 if employment declines three months straight.

Obama also pledged $10 billion to increase pre-foreclosure counseling and help "responsible homeowners" refinance their mortgages or sell their homes.

The plan also calls for $10 billion for states and local governments that have seen revenue shortfalls as a result of the housing crisis, caused by falling property values and sales tax declines.

In addition, Obama called for $10 billion to lengthen the period of eligibility for those receiving unemployment insurance, while loosening the criteria to become eligible to include many part-time and nontraditional workers.

The total package would cost $75 billion, plus another $45 billion if the economy weakened.

The plan, which expands on his campaign platform and would be financed through debt, outlines tax relief well ahead of a decision on who will secure the Democratic nomination or which candidate will win the general election in November.

The plan would need approval from the current Congress and President Bush to go forward, but the campaign put forth the plan as something Obama would pursue if he were president now.

Austan Goolsbee, a senior economic policy adviser for the Obama campaign, said Obama's plan was slightly larger than the $110 billion package advocated by his chief rival, Sen. Hillary Rodham Clinton, on Friday.

He added that it would have a more immediate impact because checks for tax credits and Social Security payments could be sent out right away, while Clinton's plan to subsidize such things as higher heating bills would require an application process.

"Those are things that would take many months if not a year or more before the money would get out the door," Goolsbee said. "If you're going to have fiscal stimulus, the absolutely most imperative thing is to get the money into people's hands immediately so that they can use it and prevent the slowdown."

The Clinton campaign noted her plan would offer more assistance on housing than Obama's — $30 billion in total — and touted her proposal to impose a moratorium on subprime-loan-based foreclosures and freeze subprime mortgage lending rates.