Japan says a plan by the South Korean government to resolve the wartime labor issue between the countries must include a guarantee that it will not ask Japanese firms for compensation payments.

Last week, South Korea unveiled the plan to use a government-affiliated foundation to offer payments to the plaintiffs in place of Japanese companies involved in the wartime labor lawsuits.

Since then, foreign ministers and senior foreign ministry officials from Japan and South Korea have held a series of exchanges.

A senior Japanese Foreign Ministry official said the proposal is definitely in the final stage of completion.

Some in the Japanese government say an agreement will only be possible if the proposal does not contradict Japan's stance that any right to claims was settled completely and finally in 1965, when Japan and South Korea normalized ties.

Tokyo believes that even in such a situation, it needs a guarantee that Japanese firms will not be required to make further payments in the future.

In 2018, South Korea's Supreme Court ordered Japanese companies to compensate people who say they or their relatives were forced to work for the firms during World War Two.