Taro Aso, son of a cement magnate and a champion of pork-barrel spending when prime minister, is Japan's sixth finance chief in three years, auguring expanded fiscal stimulus in the world's third-largest economy.

Aso, 72, will also serve as deputy prime minister and financial services minister in Prime Minister Shinzo Abe's administration.

The finance minister's first task will be to deliver on his party's pledge of a "large-scale" supplementary budget to stimulate the economy, which is forecast to shrink for a third straight quarter. At issue will be averting any selloff in the bond market as the nation grapples with debt that's in excess of twice the size of gross domestic product and as Aso calls for a new plan to restore fiscal health.