Republicans introduced a non-binding resolution in the House of Representatives that, if approved, would put the chamber on record opposing the plan, and a Senate Republican began circulating a letter to President Barack Obama saying it was critical that Congress' role in setting the limit not change.

As part of its opening bid to Republicans in talks to avoid the "fiscal cliff" of $600 billion in tax hikes and spending cuts set to hit the economy at the start of 2013, the administration proposed allowing the president to initiate hikes in the debt limit, which now stands at $16.4 trillion.

If Congress denied the request, he could then veto the decision. It would take a super-majority in both the House and Senate to override the veto, meaning the increase would almost certainly move ahead.

The White House wants any fiscal cliff deal to include a borrowing cap hike to avoid a repeat of last year's bruising debt limit fight, which unnerved markets and led to the loss of the nation's top-tier credit rating.

The idea of giving the president the authority to veto a debt limit denial was first proposed by Senate Republican leader Mitch McConnell during 2011's fight over the cap. It was put in place on a temporary basis as part of last year's broader budget deal, but the administration wants to make the policy permanent.

The idea that the president would give himself the ability "to raise the debt limit infinitely at any time he wants is the definition of insanity," said Arizona Republican Representative Trent Franks. Wyoming Republican Representative Cynthia Lummis called it "an unprecedented power grab," while Ohio Republican Representative Pat Tiberi said Obama was in "la la land."

Ohio Senator Rob Portman started gathering support for a letter to Obama expressing opposition. Congressional authority over the limit is "necessary to encourage deficit reduction and uphold our constitutional tradition of legislative control over borrowing," he said in the letter.

The debt ceiling has become the Republicans' main weapon in their fight to rein in federal spending, with more conservatives saying they might be forced to support the White House plan to raise taxes on the wealthiest as part of a deal to avert the fiscal cliff.

The government was just $86 billion below the limit on Tuesday, and was expected to hit it in the last week of December.

Although the Treasury can move funds around in order to keep paying the government's bills into early next year, the nation would eventually default if the debt cap is not raised.

Treasury Secretary Timothy Geithner said on Wednesday that a debt limit hike was an essential element of any deal to avoid the fiscal cliff.

"We are not prepared to have the American economy held hostage to periodic threats that Republicans will force the country to default on our obligations," Geithner said on CNBC.

The issue now is one of the main points of contention in budget talks. "I think the real line in the sand is going to be the debt ceiling," Republican Tennessee Senator Bob Corker said. (Additional reporting by David Lawder and Kim Dixon; Editing by Tim Ahmann and Peter Cooney)