* More than 80 Japanese nationalists near disputed islands
* Move comes amid tensions between Japan and China (Adds quotes, details, background)
By Ruairidh Villar
EAST CHINA SEA, April 23 (Reuters) - A flotilla of boats carrying more than 80 Japanese nationalists arrived on Tuesday in waters near disputed islands at the centre of tensions between China and Japan, risking further straining Tokyo's fraught relations with its Asian neighbours.
The boats were shadowed by at least 10 Japanese Coast Guard vessels, while three Chinese government surveillance ships moved near the islands, according to the JCG.
Last year members of the same group landed on one of the islets and triggered anti-Japanese protests in China, while lingering regional friction over Japan's wartime aggression also resurfaced in recent days.
South Korea's foreign minister on Monday cancelled a trip to Tokyo and Beijing blasted Japan for a lack of contrition over its past after Prime Minister Shinzo Abe made an offering to a shrine seen as a symbol of Japan's former militarism.
The nationalist Ganbare Nippon ("Stand Firm, Japan") group said the flotilla of 10 boats would sail around the rocky East China Sea islets to survey fishing grounds, and that it did not plan to land there.
It gave the same assurances when it sponsored a similar trip last August, during which about 10 activists landed on one of the islets, known as the Senkaku in Japan and the Diaoyu in China.
"This is all about asserting our ownership of the islands, going there to conduct a fishing survey to prove that Japanese fishermen can indeed make a living there," said group leader Satoru Mizushima.
"With all the provocations coming from China, we've adopted the policy that we will not land on the islands before the upper house elections (expected in July), to avoid making the diplomatic situation worse."
Tit-for-tat landings by Chinese and Japanese nationalists last summer preceded a sharp flare-up in the dispute when Japan nationalised the islands in September, drawing angry rhetoric from Beijing and anti-Japanese demonstrations across China.
The arrival of vessels in the area is part of a cat-and-mouse game being played near the Japanese-controlled islands, where China has tried to assert its claim to sovereignty by sending ships into the disputed waters.
"If you encounter problems from Chinese vessels, please run away," Mizushima, a right-wing filmmaker, told activists at a briefing before the flotilla departed from Ishigaki, a Japanese island west of Okinawa, on Monday.
"Don't let them come on board, but try to avoid fighting or shouting insults. We want to show everyone that we are polite and upstanding Japanese citizens."
Japanese ships are allowed to sail to waters around the islets, but the Japanese government generally prohibits landing.
"Landing on the Senkaku Islands is prohibited by the government. Please do not come within one nautical mile of the islands," banners carried by the coast guard ships shadowing the group read.
The waters around the islets are rich fishing grounds and also have potentially huge oil and gas reserves.
The territorial dispute has escalated in recent months to the point where China and Japan have scrambled fighter jets while patrol ships shadow each other, raising fears that an unintended collision could lead to a broader clash.
Ganbare Nippon is not officially affiliated with any political party, but its members have organised rallies to support Abe, who swept to power last December promising economic revival and a more assertive stance towards Japan's neighbours. (Additional reporting by Kiyoshi Takenaka; Writing by Antoni Slodkowski; Editing by Alex Richardson and Mike Collett-White)