Japan broke ground Saturday on a coastal surveillance unit near a string of islands at the centre of a bitter territorial dispute with China, a report said.

Radar equipment will be installed on Yonaguni island to monitor ships and aircraft in the East China Sea, the Kyodo News agency said. The island lies around 150 kilometres (100 miles) southwest of the Tokyo-controlled Senkakus, which Beijing claims and calls the Diaoyus.

The Ground Self-Defence Force surveillance unit comprising around 150 personnel will be deployed on Yonaguni by the end of March 2016, Kyodo said, citing Japan's defence ministry.

"It's very important to take a solid surveillance posture on remote islands," Defence Minister Itsunori Onodera said after attending the ground breaking ceremony, Kyodo reported.

The unit will "fill a void of SDF (Self-Defence Forces) presence" in Japan's remote southwestern islands, Onodera said.

Chinese vessels and aircraft have regularly approached the disputed East China Sea archipelago -- thought to harbour vast natural resources -- after Japan nationalised some of the islands in September 2012, setting off the latest spate of incidents in a long-running territorial row.

The ceremony comes at a time when Japanese Prime Minister Shinzo Abe is pushing to reconfigure Japan's role in the world, specifically that of its armed forces.

He wants to re-interpret a law to allow Japanese troops to take up arms to defend an ally under attack, so-called collective self-defence.

Beijing has sought to paint Abe's moves as a dangerous slide back towards its militarism of the last century.

On Saturday some Yonaguni residents opposed to the new surveillance unit scuffled with officials connected to the defence ministry, Kyodo said, adding they were concerned the island could become a target in any future conflict between Japan and China.