WASHINGTON (Reuters) - The U.S. Senate Budget Committee on Thursday voted to confirm Republican Congressman Mick Mulvaney as White House budget director under President Donald Trump.

Senators narrowly approved Trump's nominee along party lines in a 12-11 vote. Democrats criticized him for hard line fiscal positions on popular social programs and for failing to pay more than $15,000 in taxes in relation to a household employee until after he was nominated.

His nomination will now move to the Senate floor for a full confirmation vote.

Mulvaney, a South Carolina Republican and a leading member of the conservative House Freedom Caucus, favors raising the Social Security retirement age to 70 and means-testing beneficiaries of the Medicare healthcare program.

Budget committee Chairman Mike Enzi, a Wyoming Republican, told the panel Mulvaney is "uniquely qualified" to be budget director: "He is a proven budget hawk that's been vocal about our need to rein in government spending and debt."

But the nominee came under fire from Senator Bernie Sanders, an independent who ran for the Democratic presidential nomination last year.

The Vermont lawmaker warned that Mulvaney's positions on Social Security and Medicare contradict Trump's campaign statements to leave the programs untouched. Sanders also said his failure to pay taxes for a nanny he employed from 2000 to 2004 should disqualify him as a nominee.

Sanders and fellow independent Angus King of Maine voted with the committee's nine Democrats to oppose Mulvaney.

(Reporting by David Morgan; Editing by Alan Crosby and David Gregorio)