The Japanese government is set to revise a decade-old accord with the Bank of Japan that states the central bank will aim to achieve its 2% inflation target "at the earliest possible time," government sources said Saturday.

In the first review since the joint agreement was made in 2013, the government will consider making the price goal more flexible, the sources said. Prime Minister Fumio Kishida is expected to work out details with the next BOJ governor, who will succeed Haruhiko Kuroda in April.

The envisaged revision could lead the BOJ to tweak its bold monetary easing as the side effects of its ultralow interest rate policy, most notably the yen's sharp depreciation against other major currencies, have become more evident and pose a challenge for the Kishida administration.