WASHINGTON (Reuters) - A tentative deal to renew a payroll tax cut through the rest of this year likely will be finalized and voted on by the House of Representatives by the end of the week, House Speaker John Boehner said on Wednesday.

Representative Kevin McCarthy, the No. 3 House Republican, told Reuters that if a bipartisan negotiating panel signs off on the deal, as is anticipated, there will be enough votes in the House to pass it.

The proposed deal would extend a payroll tax cut for 160 million U.S. workers, extend jobless benefits for millions of others and prevent deep cuts in payments to doctors who treat elderly Medicare patients.

Speaking with reporters following a closed-door meeting of House Republicans, Boehner said, "I do expect, if the agreement comes together -- like I expect it will -- the House should vote this week."

"There is an agreement in principle," Boehner added. "But there are a lot of details that are yet to be worked out. I'm hopeful that will be wrapped up today."

One of those details has to do with the approximately $30 billion in government savings to cover the costs of the Medicare doctors' payments and extended unemployment benefits, according to three congressional sources.

The aides said that a shortfall of a few billion dollars has been discovered in the plan that would cut pension benefits for federal workers and increase government auctions of Internet and broadcast airwaves, known as "spectrum sales."

Republicans want to deepen the pension benefit cuts to make up the difference, while Democrats want to wring more savings by extending for another year higher fees on mortgages purchased by government-backed Fannie Mae and Freddie Mac that were included in December's two-month payroll tax cut extension.

The mortgage fees, currently scheduled to be in place for 10 years, equal to 0.1 percentage point on the loan amount, are due to go into effect April 1. They are expected to be passed on to borrowers in the form of slightly higher interest rates.

Negotiators were trying to work out the problem by the end of Wednesday.

McCarthy noted that traditionally when House and Senate negotiators agree on a deal, it enjoys broad bipartisan support in both chambers.

"If everybody (negotiators) signs it, I would expect it to be able to go through" the House, McCarthy said.

(Reporting By Thomas Ferraro, Donna Smith and Richard Cowan; Editing by Vicki Allen and Cynthia Osterman)