The Japanese government plans to wait and see how Russia will react after an opposition lawmaker visited the country, defying an advisory against traveling there.

Suzuki Muneo of the Nippon Ishin Japan Innovation Party is the first Japanese lawmaker to visit Russia since its invasion of Ukraine began in February last year.

Suzuki told reporters in Moscow on Tuesday that he had met a senior Russian official and requested the resumption of a program that allows former residents of four Russian-held islands to visit their ancestors' graves.

Russia controls the four islands. Japan claims them. The Japanese government maintains that the islands are an inherent part of Japan's territory. It says the islands were illegally occupied after World War Two.

The annual grave visits and other exchange programs relating to the islands have been suspended since Russia began its invasion of Ukraine.

Suzuki said he visited Russia, thinking that holding a dialogue is necessary under the current situation.

Members of the ruling and opposition blocs said the Upper House member would cause great trouble if his visit undermines Japan's national interests.

Some government officials are wary that the visit could send the wrong message to the world, because Suzuki has suggested that Ukraine is partly to blame for Russia's invasion.

But others think the visit was an attempt to grab attention.

The government plans to stay united with the other Group of Seven nations and the international community to maintain tough sanctions against Russia.

The Japan Innovation Party says that once Suzuki returns home, it will ask him why he traveled without prior notice. The party also says it will consider penalties.

Suzuki, who is known for having a close interest in Japan-Russia ties, argues that his secretary could not make the necessary notifications in time.