South Korea and China have warned Japan not to backtrack on an apology issued 20 years ago over its wartime past when Prime Minister Shinzo Abe makes a statement on the 70th anniversary of the end of World War II.

Japan's ties with South Korea and China have deteriorated in recent years as Abe has adopted a conservative agenda, including a less apologetic tone on the country's wartime past and measures to bolster Japan's global security role.

In a television interview on Sunday, the prime minister indicated that he would express remorse for Japan's role in the war in the upcoming statement, and said his Cabinet upholds past apologies, including the landmark 1995 statement by former prime minister Tomiichi Murayama. Abe suggested, however, that he would not stick with the original wording.