Japanese Prime Minister Kishida Fumio will begin a seven-day tour of Indonesia and India on Tuesday.
He is scheduled to attend the meetings of the Association of Southeast Asian Nations and the Group of 20 summit.
In Indonesia, he is expected to call on ASEAN countries to use economic cooperation and human exchanges to help maintain and strengthen a free and open international order.
This year marks 50 years of friendship and cooperation between Japan and ASEAN.
In India, the main item on the agenda at the G20 summit will be food security, which has been affected by Russia's invasion of Ukraine.
Based on the results of the G7 summit in Hiroshima, Kishida is expected to tell the G20 leaders that Japan is willing to contribute to efforts aimed at stabilizing food supplies. He is also likely to call for international efforts to address the issue.
Kishida is also expected to take every opportunity to state that the treated and diluted water being discharged from the damaged Fukushima Daiichi nuclear power plant into the ocean is scientifically safe.
He wants to obtain understanding from other nations. This comes amid China's sharp reactions to the release of the water.
The Fukushima Daiichi plant suffered a triple meltdown in the 2011 earthquake and tsunami. Water used to cool molten fuel at the plant has been mixing with rain and groundwater.
The accumulated water is treated to remove most radioactive substances, but still contains tritium.
Before releasing the treated water into the sea, the Tokyo Electric Power Company dilutes it to reduce tritium levels to about one-seventh of the World Health Organization's guidelines for drinking water.
Since the start of the treated water discharge, tritium concentrations in seawater samples have been below the detectable level in multiple checks conducted by TEPCO, the Environment Ministry and Fukushima Prefecture.
Meanwhile, the Chinese government has announced that Premier Li Qiang will attend the ASEAN meetings and the G20 summit. Observers are waiting to see whether Kishida will have a chance to speak with the Chinese premier individually.