Group of Seven leaders will express their concern over any unilateral action to change the status quo in the East and South China Seas amid tensions between China and a number of Asian countries, Japan's Yomiuri newspaper said on Saturday.
At the end of the summit in Germany, which starts on Sunday, members will release a declaration calling for maintaining an international order of seas based on international law, the report said, without citing sources. No country will be singled out.
G7 leaders a year ago expressed their concern about tensions between China and a number of other Asian countries over resources in the East and South China Seas, and warned against any use of force.
China claims most of the South China Sea, through which $5 trillion in ship-borne trade passes every year. The Philippines, Brunei, Malaysia, Taiwan and Vietnam also have overlapping claims.
All but Brunei have fortified bases in the disputed waters, which are roughly 1,300 km (800 miles) from the Chinese mainland but much closer to the Southeast Asian claimants.
Japan also has a territorial row with China over islands in the East China Sea.
China has been criticized for extensive reclamation work and moves to turn submerged rocks into man-made structures. The United States last week said Beijing had placed mobile artillery systems in contested territory.