Image copyright AFP Image caption About 47,000 well-wishers attended the emperor's annual New Year speech, where he called for peace

Japan is considering legal changes to allow Emperor Akihito to abdicate at the end of 2018, say local media reports citing government sources.

Crown Prince Naruhito could then ascend the throne on 1 January 2019, according to the reports.

Akihito, 83, hinted in August that he wanted to stand down, saying his age could interfere with his duties.

No Japanese emperor has abdicated for two centuries and the law currently does not allow it.

Image copyright Getty Images/Asahi Shimbun Image caption Akihito, who has had heart surgery and been treated for prostate cancer, has been on the throne since his father died in 1989

The abdication itself could take place on 31 December 2018, with Akihito's 56-year-old son taking over the next day, the reports said.

Rather than permanently changing the law to allow emperors to quit, the change being considered would be a one-off exception.

That would sidestep controversy amongst conservatives about changing succession laws, including whether to allow women to ascend to the Chrysanthemum Throne - something the Japanese public is thought to support but which has long been opposed by ultra-conservative politicians.

A six-member advisory panel to Prime Minister Shinzo Abe has been discussing the issue since October, and is expected to issue its report as early as May.

Chief Cabinet Secretary Yoshihide Suga denied knowledge of any consensus over how to proceed, telling reporters things were "still at a stage where no direction has emerged".

Image caption With Akihito having only granddaughters until 2006, Japan has often debated whether to allow female succession

Akihito, who has had heart surgery and was treated for prostate cancer, has been on the throne since the death of his father, Hirohito, in 1989.

He has not explicitly said he wants to abdicate, as he is barred from making political statements.