TOKYO - Japan yesterday asked South Korea to go to the International Court of Justice (ICJ) for a ruling on a disputed island chain, as Tokyo looks to get some diplomatic leverage in a damaging row.

Foreign Minister Koichiro Gemba delivered the proposal to the South Korean ambassador to Japan during a meeting in Tokyo.

It is the first time that Tokyo has asked Seoul to go to the ICJ for five decades, and the first since ties with its one-time colony were normalised.

"I hope (South Korea) will accept it with its head held high," Prime Minister Yoshihiko Noda told reporters in Tokyo, according to Jiji Press.

Ties went into virtual freefall when South Korean President Lee Myung Bak last week visited the Seoul-controlled islands - known in Japan as Takeshima and in Korean as Dokdo - in the Sea of Japan.

His comments earlier this week that Emperor Akihito must apologise for Japan's warmongering past if he wanted to visit South Korea also caused anger.

However, Japan may find it difficult to bring the island issue to The Hague-based ICJ, which will not hear the case unless the two contending parties agree to the referral.

In Seoul, Foreign Ministry spokesman Cho Tai Toung said: "We affirm that Japan's proposal is not worthy of consideration."

As part of Japan's protest against Mr Lee's visit to the islands, Japanese Finance Minister Jun Azumi yesterday announced he was cancelling a planned trip to South Korea and suggested reviewing a bilateral currency swap deal.

An existing swap agreement between the two sides was expanded to US$70 billion (S$87.7 billion) in October from US$13 billion. The swap was designed to offer the countries protection from funding shocks as demand in their largest export markets slows and Europe's debt crisis deepens.

"There is nothing to worry about even if Japan decides against extending the currency swap because South Korea already has the Chiang Mai Initiative," said South Korean presidential spokesman Lee Mi Yon.

Japan, China, South Korea and Asean countries agreed in May to boost the so-called Chiang Mai Initiative, which involves a pool of foreign-currency reserves, to US$240 billion from US$120 billion.

AGENCE FRANCE-PRESSE, XINHUA, BLOOMBERG