The plan involves sending an SDF vessel and a patrol plane to waters near the Strait of Hormuz, according to NHK.
Japanese Prime Minister Shinzo Abe raised the matter in talks with Iranian President Hassan Rouhani in Tokyo on Friday.
The Japanese government said after the meeting that it has gained a certain level of understanding from Iran.
Abe explained the details and conveyed Tokyo's willingness to continue diplomatic efforts to ease tensions in the Middle East.
Rouhani responded by praising those efforts.
He said he understands that Japan wants to take an active role in ensuring safe navigation for ships. He said he appreciated Japan's transparency on the matter.
The government is now making adjustments to have the plan approved at a Cabinet meeting.
MNA/PR