New crew members will operate two extra jets that will be deployed in the next 12 months to strengthen patrols around the Senkaku Islands, according to a spokesman from the Japan Coast Guard.

"We'll boost our aviation crew by bringing in 60 more members," the spokesman told AFP.

Japan will deploy two Falcon 2000LXS jets this fiscal year and one more plane next year to allow a "24-hour patrol system" to monitor the disputed islands, known in China as the Diaoyus.

The move comes after Japan spotted a Chinese nuclear-powered submarine in disputed waters early this year.

The uninhabited islets are at the centre of a festering row between Tokyo and Beijing, which is also involved in a widening dispute with several Southeast Asian countries over islands in the South China Sea.

The Japanese government has long complained about China's routine dispatch of coast guard ships to waters surrounding the islands.

Relations between Japan and China deteriorated in 2012 when Tokyo "nationalised" some of the islets.

Since then, the two top Asian economies have taken gradual steps to mend fences but relations remain tense.