Japan's top government spokesperson says the country will urge Russia to allow Japanese fishing boats to operate as soon as possible around four Russia-controlled northern islands claimed by Japan.

Chief Cabinet Secretary Matsuno Hirokazu spoke to reporters on Monday, days after Russia informed Japan that it cannot hold annual talks this year to decide the details of the boats' operations in waters around the islands. The details include the fishing period and catch amounts.

The annual talks are based on a bilateral agreement signed in 1998.

Matsuno said the pact ensures the safe operations of Japanese fishing vessels in waters around the Northern Territories. The four islands have been a long-standing issue between the two countries.

He said Japan and Russia have maintained and advanced the operations in a mutually beneficial manner for more than 20 years.

Matsuno called Moscow's notification unacceptable. He said Japan will urge Russia to hold the annual talks as soon as it can.

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