A key Democratic senator told FOX News on Monday that he wants to strip "tens of billions" of dollars from the economic stimulus proposal, rejecting the White House claim that senators are complaining about just a tiny fraction of the package.

Nebraska Sen. Ben Nelson, who sits on the Senate Appropriations Committee, said Republicans and Democrats alike want to gut the nearly $900 billion program of items that he says will not stimulate job growth.

President Obama and his aides have downplayed disagreements over the package as it comes before the Senate for debate. Obama said Monday that "modest differences" should not stall the package, and Press Secretary Robert Gibbs said GOP objections center on about $700 million worth of items -- or "seven one-hundredths of one percent" of the total package.

Not so, said Nelson.

"It's more money than that," he said. "We're talking in the billions, and tens of billions, that we're looking to exclude from this particular program."

He singled out provisions in the bill for programs like U.S. Department of Agriculture computers and medical research as items that are worth funding -- but not in a stimulus package.

Lawmakers like Nelson, along with Republican congressional leaders who are noisily slamming the program, could complicate the administration's efforts to push through the stimulus in the days ahead.

Senate Republican Leader Mitch McConnell said Monday that the plan must do more to address housing and make mortgages more affordable. He said the package his colleagues would support must be "dramatically different" than the $819 billion version that passed on the House side last week without any Republican support.

"Nobody that I know of is trying to keep a package from passing," McConnell said. "We're trying to reform it."

Wisconsin Democrat Russ Feingold also released a statement saying the bill must not include wasteful spending and should direct funding to job-creating projects.

"Any amendments or provisions that would add to our deficit need to stimulate the economy; otherwise, they should be paid for," the senator said.

Gibbs would not say how the bill might be re-shaped on the Senate side.

"The bottom line is this -- you've got a piece of legislation that creates jobs," Gibb said. "I'm gonna leave the legislating to the legislators."

Grover Norquist, president of Americans for Tax Reform, said part of the problem for Obama is that some Democrats, and many Republicans, can't afford to vote for the measure.

"Some people will lose their jobs for voting for this measure. Nobody will be harmed by voting against it," he said.

Norquist, who vehemently opposes the stimulus package, said he expects the Senate to craft a plan that is "slightly less horrific."