Washington: US President-elect Barack Obama has chosen Timothy Geithner as Treasury secretary and Lawrence Summers as director of the White House National Economic Council, a transition aide said.

Obama plans to formally announce his choices at a news conference on Monday.

Obama has already announced that close aide Robert Gibbs would be White House press secretary and Ellen Moran of the women's organisation Emily's List would be director of communications.

Meanwhile, US stock prices rallied more than 6 per cent on Friday after word leaked out that Geithner appeared set to take the Treasury post.

Summers and Geithner worked closely together during the 1990s in fighting global crises.