WASHINGTON (AFP) - President Barack Obama on Friday will name former Pentagon deputy chief Ashton Carter to be his new defence secretary, a White House official said.

If confirmed Carter would replace Chuck Hagel, who announced his resignation last month. Carter served as deputy defence secretary under Leon Panetta from October 2011 to December 2013.

Obama will make the announcement later Friday morning, joined by both Carter and Hagel, a White House official said on condition of anonymity.

Carter, 60, has gained a reputation as an expert on hi-tech weapons and military budgets, portraying himself as a reformer intent on making the vast Pentagon bureaucracy more efficient.

But he has less experience overseeing war strategy and has never served in uniform, unlike Hagel, who was wounded in the Vietnam War.