Former economy minister Akira Amari said Monday he will resume political activities "step by step" after prosecutors decided last week not to charge him with graft over money-for-favors allegations.

"I deeply apologize to the people for causing tremendous nuisance and worries," the veteran lawmaker of the ruling Liberal Democratic Party said at a news conference in his electoral district in Kanagawa Prefecture.

Amari, who was known as Prime Minister Shinzo Abe's right-hand man in the Cabinet as minister of economic and fiscal policy, had stopped attending parliamentary meetings on medical grounds since he resigned from his Cabinet post over the allegations in late January.