Russia and Japan have yet to sign a formal treaty ending World War II hostilities, due to their territorial dispute over the four South Kuril Islands, former Japanese territory annexed by the Soviet Union after the war.
"This [peace treaty] can only be done in a way that will meet the national interests of the Russian Federation," Putin told reporters.
He said the content of a peace treaty would be a focus of future bilateral negotiations.
The premier said on Tuesday that President Dmitry Medvedev would discuss territorial issues and a formal peace treaty with Japanese Prime Minister Taro Aso at the upcoming G8 summit in Italy.
Putin visited Tokyo on Tuesday to discuss the long-standing dispute, along with economic, energy and international issues.