A group of Japanese lawmakers applied on Friday to buy customised postage stamps showing a group of islets claimed by both Japan and South Korea in a long-standing territorial row.
The move could strain bilateral ties, coming just days before South Korean Foreign Minister Ban Ki-moon visits Japan and as Seoul steps up its criticism of Japanese Prime Minister Junichiro Koizumi's visit to a controversial shrine for war dead.
A row over the rocky outcrops known as Takeshima in Japan and Tokto in South Korea flared in January when Seoul issued stamps featuring the flora and fauna of the islands despite protests from Tokyo. The 2.24 million stamps sold out in about two hours.
Masahiro Morioka, a member of the ruling Liberal Democratic Party, led six lawmakers in applying for stamps showing the outline of the islands under a recently introduced system whereby customers can have stamps made with their favourite images.
"It's a historical fact that these islands are Japanese territory, but South Korea issued stamps in January to emphasise their claim that the islands belong to them," Morioka said. "We had to respond to this."
The dispute over the islets, uninhabited except for a garrison of South Korean soldiers, has run since the end of World War Two and the stamp fracas has brought it to life again.
Morioka's group also applied to order stamps depicting two other disputed island groups - the Senkakus, claimed by Japan and China, and the Northern Territories, four islands at the centre of a row between Japan and Russia.
An official at Japan Post, the government-backed organisation in charge of Japan's postal system, accepted the applications but said no decision could be made without consulting other branches of the government, including the Foreign Ministry.