Japan plans to revise its Medium Term Defense Program earlier than originally scheduled as it looks to boost spending to counter China's growing assertiveness in surrounding waters and prepare for contingencies in the Taiwan Strait, government sources said Friday.

The program, which covers the five years through fiscal 2023, could be updated within the year, with Prime Minister Yoshihide Suga and Defense Minister Nobuo Kishi having agreed earlier this month that some changes are necessary, the sources said.

Discussions between officials including at the Defense Ministry and the National Security Secretariat are already underway, with budget issues set to be reviewed by the Finance Ministry.