Roh Moo-hyun said in a three-page letter addressed to the South Korean public that recent disputes can be called attempts by Tokyo to justify a past he sees as colonialist and expansionist.(Reuters)

South Korean President Roh Moo-hyun says his country is ready for a "diplomatic war" with Japan as tensions flared between the neighbours over a territorial row and a Japanese textbook critics say whitewashes Japan's militarism.

Roh Moo-hyun said in a three-page letter addressed to the South Korean public that recent disputes can be called attempts by Tokyo to justify a past he sees as colonialist and expansionist.

He said that South Korea's determination to set Japan right "may cause stinging diplomatic war", but pledged to press Japan to take actions he saw as corrective and persist until Tokyo "listens and does what it rightly has to do."

The comments were the strongest ever on Japan from Roh, who until last year vowed not to let the history get in the way of improving ties with Tokyo.

South Korea's anger was triggered when a local Japanese assembly last week passed a symbolic measure asserting Japan's claim to desolate islands, called Tokto in Korea and Takeshima in Japan, and claimed by both nations.

South Korea has also awaited the result of Tokyo's review of a new history textbook, which critics say whitewashes Japanese military atrocities in Asia and its brutal colonial rule over Korea.

Editor: Olivia