Japan on Thursday indicted a Chinese trawlerman whose ramming of two Japanese coastguard vessels sparked a diplomatic showdown, in a symbolic move that was likely to fizzle out.

The formal indictment came after an independent review panel overturned a decision by prosecutors to drop charges against captain Zhang Qixiong over the incident near disputed islands in the East China Sea.

The move angered some in Japan, who felt Tokyo climbed down in the face of Chinese sabre-rattling in a long-rumbling territorial dispute over the islands, which are known as Senkaku in Japan and Diaoyou in China.

Now two court-appointed lawyers, serving as prosecutors, have formally charged the 42-year-old captain, even though he is in China and highly unlikely to respond to the move.

"We brought a prosecution against him for obstructing the performance of official duties, inflicting damage on vessels and violating the law regulating fishing operations by foreigners," one of the lawyers, Shinya Akamine, said.

The prosecution will almost certainly falter as there is no extradition treaty between the two countries, who in any case sharply disagree over the rights and wrongs of the September 2010 case.

In Beijing, Chinese foreign ministry spokesman Liu Weimin, referring to the indictment, told a news conference: "We hope that Japan will do more to preserve the broad picture of bilateral relations and not the opposite."

Relations between Tokyo and Beijing went into freefall after Zhang was arrested following the collisions near the uninhabited, but strategically coveted island chain.

Zhang was freed and returned to China 18 days later, with Japan widely seen as having received a diplomatic bloody nose after apparently bowing to pressure from Beijing, which cancelled exchanges and blocked trade.

In February last year, the Japanese coastguard reportedly sent Zhang a $170,000 bill to cover repairs to its damaged ships and other expenses stemming from the collision.

The territorial row was refuelled in August after Tokyo protested to Beijing over the entry of Chinese fishery patrol boats into waters near the islands.

The string of five small islands lies between Japan's far-southern Okinawa island and Taiwan in an area believed to hold seabed oil deposits.

Controlled by Tokyo, but also long claimed by Beijing and Taipei, the uninhabited islands have often sparked regional tensions.