EAST CHINA SEA – Boats carrying about 20 members of a Japanese nationalist group headed back to port on Sunday after sailing near tiny islands in the East China Sea that are at the centre of a dispute between Japan and China.

Members of the Ganbare Nippon ("Stand Firm, Japan") group did not attempt to land on the uninhabited islands, which are known as the Senkaku in Japan and Diaoyu in China, but had said they wanted to send a message to China.

"We want to show these islands are under Japanese control," Satoru Mizushima, the right-wing film maker who leads Ganbare Nippon, told activists before departure late on Saturday from a port in Okinawa.

The islands are located near rich fishing grounds and potentially large oil and gas reserves.

The five Ganbare Nippon ships were surrounded by about 10 Japanese coast guard vessels when they approached within 1 nautical mile of the islands on Sunday morning. Coast guard crews in rubber boats urged them to leave through loudspeakers.

Last week, Chinese patrol boats entered Japanese territorial waters and stayed there for more than 24 hours, the longest since surveillance around the islands was increased after Japan's government purchased several of them from a private owner in September last year.

No Chinese vessels were reported in the vicinity on Sunday, although Chinese and Japanese planes and patrol vessels have been playing cat-and-mouse near the islands, raising concerns that an unintended incident could escalate into a military clash.

The trip by the right-wing Japanese group comes days after Japanese Prime Minister Shinzo Abe sent an offering to Tokyo's Yasukuni Shrine for war dead - seen by critics as a symbol of Japan's past militarism - on the anniversary of Japan's World War Two defeat.

Ganbare Nippon is not officially affiliated with any political party but its members have organised rallies to support Abe and visited Yasukuni en masse on Thursday, carrying Japanese flags and banners.

Last August, activists from Hong Kong landed on one of the disputed islands and were detained by Japanese authorities before being deported.

That incident triggered a wave of protests across China that grew larger after Japan's then-Prime Minister Yoshihiko Noda agreed to buy three of the islands from a private landowner. By buying the islands, Noda had intended to prevent friction from heightening with Beijing and Taipei by thwarting a rival bid from a nationalist politician.

Shintaro Ishihara, then the governor of Tokyo, had led a fund-raising drive to buy the islands and build on them.

Abe, who came to power last year and consolidated his grip on power with a solid victory in elections to the upper house in July, has called for dialogue with China and sent advisers to Beijing, trying to improve ties. China's public response to the overture has been chilly.