SEOUL—North Korea has created a new ruling organization in an apparent continuation of efforts by leader Kim Jong Un to shift political power away from the military and spur economic revival.

A meeting of Pyongyang’s rubber-stamp parliament Wednesday approved the formation of the State Affairs Commission to replace the National Defense Commission as the highest branch of government, according to a report from North Korea’s state news agency.

The military-dominated NDC has for years been the supreme governing authority in North Korea. Under the “military-first” policy of Kim Jong Il, North Korea’s ruler from 1994 to 2011 and father of the current leader, the NDC directed policy in areas such as the economy and foreign relations as well as national defense.

During that period, military figures took control of projects such as trade and mining, funneling resources to the armed forces. Kim Jong Un has sought to revive the role of the ruling Workers’ Party by asserting his own authority over the military and emphasizing the party in decision-making.

In May, North Korea held its first party congress since 1980. Since taking power, Mr. Kim has rotated out or purged dozens of generals, widely interpreted as measures to rein in military authority.