By Antoni Slodkowski and Junko Fujita
TOKYO (Reuters) - Tokyo Governor Shintaro Ishihara, a fiery nationalist whose failed bid to buy a group of disputed islands ignited a crisis with China, is pushing ahead with a plan to build structures there to hammer home Japan's claim, officials involved told Reuters.
Although such a move is not imminent, it would be certain to strain Japan's already shaky relations with China and could prompt a rebuke from the Obama administration, which has urged both sides to ease tensions by setting aside the dispute.
Ishihara's gambit appears aimed at forcing a new showdown in the island dispute with China. It is based on the view that Japan's main opposition -- the conservative Liberal Democratic Party (LDP) -- is likely to take power in an election in the coming months and that it would be receptive to his hard-line policies, two officials close to Ishihara said.
Akiko Santo, a member of the House of Councillors from the LDP, said Ishihara would try to win support from a new government to use about $19 million he has raised from contributors to build some basic infrastructure on the islands.
Ishihara's deputy, Naoki Inose, has confirmed the plan.
They claim that construction of a lighthouse, radio transmitter or basic harbor facilities would increase safety for Japanese fishermen. It was not clear how -- or even whether -- such private funds could be used for construction on government property.
Ishihara set off the slide in Japan-China relations with his initial bid to buy the islands, ensuring his next steps in the dispute will be scrutinized.
Narushige Michishita, an associate professor at the National Graduate Institute for Policy Studies in Tokyo, said Ishihara's push could "re-create the situation we have just gone through -- strong reaction from China followed by demonstrations and attacks on Japanese companies."
That effort was thwarted when the national government outbid Ishihara last month with a taxpayer-funded bid to acquire three of the isolated islands called the Senkaku in Japan and Diaoyu in China.
Prime Minister Yoshihiko Noda's nationalization of the islands was intended to keep them from Ishihara and to head off a more damaging confrontation with China.
But the Japanese government's move triggered a wave of protests in China that shuttered Japanese factories and stores, disrupted trade and prompted Beijing to strengthen its own claim to the disputed territory.
China has claimed the islands as its "sacred territory" and says its claim predates Japan's. Patrol ships from the two countries have been circling in a standoff in the waters off the disputed islands, raising concern that a collision or other incident could escalate into a bigger clash.
Now an independent, Ishihara has been governor of Tokyo since 1999. A former LDP member and author, he is best known for writing "The Japan that Can Say No," a 1989 book that urged Japan to step away from reliance on the United States.
The LDP is expected to capitalize on frustration with Noda's government and his Democratic Party of Japan, which took power in 2009 but has been criticized for its response to last year's earthquake and nuclear disaster and its economic stewardship.
Last month, former prime minister Shinzo Abe was elected to lead the LDP as the party heads into an election that could be called before year end. Abe's selection as his chief aide, Shigeru Ishiba, is a defense expert who has argued Japan should take stronger action to protect territory it claims in disputes with China and South Korea.
Ishihara began raising private contributions from supporters earlier in the year to buy the islands in the East China Sea.
"The funds will be used when something can be done together with the LDP," said Santo, an Ishihara ally who had tried to broker Tokyo's effort to buy the islands from the family that has owned them since the late 1970s.
Tokyo vice governor Inose added: "With an Ishiba or Abe government we could use the funds we have raised to build some kind of shelter for ships or a transmitter or lighthouse."
Ishihara, 80, had said on September 11 -- the day the national government signed a contract to buy the islands -- that the Tokyo government could hand over the money it raised "if the next administration agreed to build a minimum of infrastructure" on the disputed territory.
Inose and Santo indicated those plans were still moving ahead even after the wave of costly protests in China and the escalating tension between the two sides over the past month.
Recent opinion polls show the LDP as more popular than the center-left DPJ and Abe as having more support than Noda among Japanese voters. That could create a new opening for Ishihara to push his plans for the disputed islands.
Noda, 55, said last month his priority was to "maintain stable administration" over the islands and questions of any construction on the property should be taken up later.
"We are already maintaining and controlling (the islands) in a calm and stable manner," Japan Foreign Koichiro Gemba said on Wednesday when asked about proposals to build on the islands.
By contrast Abe, 58, said during his campaign for LDP leadership that he would consider setting up a shelter for fishing boats and facilities where civil servants can stay permanently to strengthen Japan's control over the islands.
Now that Abe has taken the LDP's helm, his stance on territorial disputes will be reflected in the party's policy, an LDP official in the party's policy planning wing said.
"I think Abe and Ishiba are of the same mind here (as Ishihara)," Santo told Reuters. "Of course, all of this depends on the LDP taking back power in the next election."
(Additional reporting by Kiyoshi Takenaka, writing by Kevin Krolicki; Editing by Raju Gopalakrishnan)