Japan's Supreme Court has set rules on the permanent preservation of trial records, following revelations that the documents of some high-profile trials had been lost at courts across the country.

Officials say the new rules will be effective as of January next year.

The top court set up a panel of experts after the discarding of high-profile trial records came to light. One of the lost records covers a 1997 serial murder case in the city of Kobe, in which a 14-year-old boy killed two children and injured three others. In May, the court released a report on what's behind the problem, as well as how records should be maintained.

The rules state that records of historical and social significance should be passed on to future generations as a shared possession of the nation. They also call for the establishment of a permanent third-party committee to advise whether records should be kept in perpetuity.

In addition, the new rules will allow members of the public to ask a court to preserve the records of a trial permanently. The court can decide not to do so, but only after it consults with the third-party panel.

The top court also revised the rules on how records should be disposed of. According to the revised rules, any disposal of records will require confirmation from the chief of a court in charge.

The secretary general of the Supreme Court, Hotta Masaya, said he will do everything to ensure appropriate operations to preserve records in accordance with the rules.