Nevertheless, Gregg said he agreed that the economy needed a "robust stimulus," and added, "I want to work with the other side of the aisle and with the president-elect to accomplish it, because I don't think we can afford partisan politics at this time. We need to govern."
In his remarks at George Mason University, Obama said his plan would revive the economy and benefit the country's infrastructure.
"It is not just another public works program," he said. "There are millions of Americans trying to find work, even as, all around the country, there is so much work to be done."
Obama spelled out in broad terms today what much of the money would be spent on, including:
Doubling the production of alternative energy in the next three years.
Modernizing more than 75 percent of federal buildings and 2 million homes to make them more energy efficient.
Computerizing all of America's medical records within five years.
Equipping thousands of schools and colleges with modern classrooms, labs and libraries.
Expanding broadband across the United States.
Obama acknowledged that he was making his pitch after the Bush administration has spent trillions of dollars on bailouts, only to see the nation's fiscal prospects sour even more as critics worry that resulting deficits could last for generations.
"Our government has already spent a good deal of money, but we haven't yet seen that translate into more jobs or higher incomes or renewed confidence in our economy," Obama said.
When Obama takes office Jan. 20, he will inherit an economy that has been in recession for a year and has lost more than 2 million jobs, the most in any year since World War II.
What Obama is proposing, he said, is "not just a new policy, but a whole new approach" that includes a financial rescue and economic reform.
"This crisis did not happen solely by some accident of history or normal turn of the business cycle," he said. He blamed "an era of profound irresponsibility that stretched from coorporate boardrooms to the halls of power in Washington, D.C."
What is needed, he said, is to "trade old habits for a new spirit of responsibility."
What is also needed is a sense of urgency, Obama said.
"For every day we wait or point fingers or drag our feet, more Americans will lose their jobs. More families will lose their savings," he told his audience.
In a demonstration of support for Obama's plan, six governors and 14 mayors attended the speech. They included New York City Mayor Michael Bloomberg, who is an independent, and Virginia Gov. Tim Kaine, who has been designated the next chairman of the Democratic National Committee.
Obama conceded that the government can't simply spend itself out of the economic crisis that is a tangle of tight credit, spiraling bankruptcies, job losses and loss of faith by consumers.
But, he argued, "only government can break the vicious cycles that are crippling our economy."
The soon-to-be-president admitted that the size of the rescue plan is massive.
"There is no doubt that the cost of this plan will be considerable. It will certainly add to the budget deficit in the short-term," he warned. The first year of his administration is expected to have a record-breaking budget deficit of $1.2 trillion, according to a projection released Wednesday by the Congressional Budget Office.