According to the nonpartisan Congressional Budget Office, White House-backed legislation in the Senate to replace $85 billion in across-the-board spending cuts would raise the deficit through the end of the budget year by tens of billions of dollars.
Democrats have said their plan would spread the cuts over a decade to avoid damage to the economy.
President Barack Obama says looming automatic budget cuts will cause a "tumble downward" for the economy.
He acknowledges many people may not immediately notice the full impact of the so-called sequester cuts if they take effect Friday.
But he says yanking $85 billion from the economy this year would be a "big hit" on a nation still trying to fully recover from a recession.
Speaking to business executives Wednesday, Obama acknowledged it will be difficult for lawmakers to reach a deal to offset the cuts by Friday.
He says the logjam is not technical, "it's political."
The President wants Republicans to drop their opposition to using some new tax revenue to offset the cuts. And he says members of his own party must accept some changes to government entitlement programs.