WASHINGTON DC (REUTERS) - US Vice-President Joe Biden stole the show at the swearing-in of new US Defense Secretary Ash Carter on Tuesday by exercising his avuncular manner and getting close to Carter's wife Stephanie.

Mr Biden swore Mr Carter in at a White House ceremony after the US Senate overwhelmingly voted to confirm him last week.

The newly sworn-in 60-year-old served from 2011 to 2013 as deputy defense secretary, the Pentagon's No. 2 position. He was confirmed by a vote of 93-5 on Feb 12.

In a message to Department of Defence staff that was made public by the Pentagon, Mr Carter said a top priority would be dealing with congressional funding limits that create "wasteful uncertainty" for defense programs.

"To win support from our fellow citizens for the resources we need, we must show that we can make better use of every taxpayer dollar," he said.