In the latest territorial flap between South Korea and Japan, a bipartisan group of lawmakers voiced concern Wednesday over growing South Korean capital investment in Nagasaki Prefecture's Tsushima, an island city only 50 km from the Korean Peninsula.

"Numerous numbers of guesthouses and inns for sport fishermen have been purchased by South Koreans," Lower House member Takeo Hiranuma said at a meeting in Tokyo. "Some land adjacent to Japan Coast Guard property has also been purchased by them."

In July, 50 South Korean lawmakers handed a resolution to their legislature demanding that the government claim Tsushima, known as Daemado in Korean, as its territory. The island, which has a population of 37,000, saw 65,000 South Korean visitors in 2007.