WASHINGTON (Reuters) - Republican efforts to scrap President Barack Obama’s healthcare reform took a hit on Thursday when budget analysts said repeal would add billions of dollars to the federal budget deficit.

The nonpartisan Congressional Budget Office estimated overturning the reform signed by Obama last year would add about $230 billion to the deficit by 2021 and result in 32 million fewer people having health insurance.

That was a blow to Republican campaign promises to slash the federal budget deficit.

Democrats, who control the Senate despite losses in last year’s elections, promised to protect the healthcare law, Obama’s signature legislative victory.

“The Republicans have to understand that the healthcare bill is not going to be repealed,” Senate Democratic leader Harry Reid told reporters.

“We’re willing to work in any way that’s constructive in nature to improve the healthcare delivery system for our country,” he said. “But repealing healthcare? They should get a new lease on life and talk about something else.”

The law is designed to rein in medical costs, cover millions of uninsured people and reform insurance practices, including requiring coverage for patients with pre-existing conditions and other consumer protections.

The Republican-controlled House of Representatives will vote on repealing the law next week in what will largely be a symbolic gesture given the Senate’s likely opposition.

In a preliminary estimate, the CBO said repealing the healthcare overhaul would increase the federal budget deficit by roughly $145 billion by 2019. That figure would rise to about $230 billion by 2021, it said.

New House Speaker John Boehner, who has promised to bring down the $1.3 trillion federal deficit, disputed the numbers.

“CBO is entitled to their opinion,” Boehner told reporters. “When you look at it dollar by dollar, you can tell that the numbers just don’t add up.”

Debate on repeal of the healthcare law, another core Republican promise during the 2010 campaign, is scheduled to begin in the Republican-controlled House on Friday with a vote planned for next week.

Bonnary Lek, a manager at Discovery Communications headquarters, is examined by Discovery Wellness Center Medical Director Liz Sequeira during an appointment at the clinic in Silver Spring, Maryland December 3, 2009. REUTERS/Jim Bourg

PUBLIC OPINION SPLIT

Polls show public opinion on the law is split, but Republicans won control of the House last year after promising to repeal it.

They argue the law places job-killing burdens on business and is unconstitutional because it requires individuals to purchase health insurance if they are not already covered.

Democrats pounced on the report by the CBO, which analyzes legislation for its impact on government spending and revenues and develops forecasts of U.S. economic performance.

Representative George Miller said it showed the Republicans’ “budget-busting repeal bill will kill jobs, raise costs and deny critical care to Americans who need it.”

A House committee began a meeting on Thursday to put together rules governing the House floor debate of the healthcare law. The panel is eventually expected to refuse to let Democrats offer amendments on the bill that could pass as soon as January 12.

Another key battle over healthcare reform could come by March when a temporary funding measure for the government runs out. Republicans balked at $1 billion to start implementing the healthcare law as part of a bigger appropriations bill that Democrats tried and failed to move last year.

Lawmakers instead opted for a stop-gap measure that keeps funding mostly at current levels through March 4.