German Chancellor Angela Merkel reportedly told Japanese counterpart Shinzo Abe last year that his country could joint NATO counting on her support.

"Shinzo, why not join the North Atlantic Treaty Organization? I can convince British Prime Minister Cameron and French President Hollande," The Japan Times, the country's biggest English-language paper, quotes Merkel as saying.

Merkel allegedly told Abe in March of last year she would convince British Prime Minister David Cameron and French President Francois Hollande.

Japan and Russia have long been caught in a dispute over the disputed islands referred to as the Northern Territories by Tokyo and the Kuril Islands by Moscow.

Abe reportedly said if Japan joined now, negotiations with Russia over the territories would stop.

German authorities are yet to comment on the report, which comes at a time when many in Germany and the rest of Europe have criticized Merkel's policies with regard to the migrant inflow and, earlier, the euro crisis.