Tokyo and Seoul have long been at loggerheads over the sovereignty of the group of islets called Takeshima in Japanese and Dokdo in Korean, which lie about halfway between the East Asian neighbours in the Sea of Japan, also known as the East Sea.
The military drills were scheduled to begin on Sunday, and will include naval, air, and army forces, a South Korean ministry of defence official said.
The Japanese foreign ministry called the drills unacceptable and said it had lodged a protest with South Korea calling for them to end.
The island is “obviously an inherent part of the territory of Japan”, Kenji Kanasugi, the director general at the ministry’s Asian and Oceanian Affairs Bureau, told the South Korean Embassy in Tokyo in a statement.
Tensions in the region have spiked amid a worsening political and economic spat between South Korea and Japan, a string of missile launches by North Korea, and increasingly assertive military patrols by China and Russia.
South Korea announced the scrapping of an intelligence-sharing pact with Japan on Thursday, drawing a swift protest from Tokyo and deepening a decades-old dispute over history that has hit trade and undercut security cooperation over North Korea.
Relations between South Korea and Japan began to deteriorate late last year following a diplomatic row over compensation for wartime forced labourers during Japan’s occupation of Korea.
They soured further when Japan tightened its curbs on exports of high-tech materials needed by South Korea’s chip industry, and again this month when Tokyo said it would remove South Korea’s fast-track export status.
The disputed islands have long been one of the most sensitive areas of contention for South Korea and Japan.
The defence drills around the islands have typically been conducted twice a year, but the current exercises had been delayed as relations deteriorated, Yonhap news agency reported.
In July South Korea and Japan responded to what they saw as a violation of their air space near the islands by a Russian military plane.