Japanese officials are set to declare their support for a global ban at the Convention on Certain Conventional Weapons in Geneva later this month, the newspaper Sankei Shimbun reported.
Tokyo had earlier been reluctant to support a ban, saying it needed the bombs for self-defense. But Japan has decided to back a delayed ban to pre-empt a push by some countries for an immediate curb, the Sankei said.
Defense Ministry officials were not available for comment Sunday.
Last month, Japan's defense minister said Japan will never use cluster bombs to attack other countries.
Cluster bombs open in midair, scattering smaller bombs across large areas to hit airfields, tanks, missile sites and troops and vehicles. When the "bomblets" fail to explode, they remain hazardous for a long time and can explode when touched.
The weapons have been used over the past 60 years in at least 17 countries, including Vietnam, Cambodia, Iraq, Afghanistan and Serbia's Kosovo province.
The United States and Russia, which both hold significant stockpiles, have so far refused to support an outright ban on cluster bombs.