Japan Post Holdings Co. said Wednesday it will promote Deputy President Atsuo Saka to its top post, replacing Jiro Saito.

Saka, 65, who became deputy chief in 2009, was previously an official in the Finance Ministry and held various key government posts, including assistant chief Cabinet secretary in 2006 when Shinzo Abe, who is set to again become prime minister next week, was chief Cabinet secretary.

Saito has decided to step down after setting the course for streamlining the company's operations. A government panel Tuesday approved new business plans for Japan Post's two finance units. The holding company, which has Japan Post Co., Japan Post Bank Co. and Japan Post Insurance Co. under its wing, wants to go public by 2015 and is expected to gain as much as ¥7 trillion by selling two-thirds of its shares.

Saka will be tasked with making arrangements on the large-scale listing with the government to be led by Abe and his Liberal Democratic Party. Saito, 76, a former top Finance Ministry official, assumed the top post in the group in October 2009. He played a pivotal role in enacting the postal service privatization law last April and realigning mail delivery and over-the-counter services in October.