Emperor Akihito visits the House of Councillors in Tokyo on Jan 20, 2017, as parliament starts an ordinary session. [Photo/IC]

TOKYO - Japan is moving to adopt a law allowing its octogenarian Emperor Akihito to abdicate but many touchy topics, such as his title and duties, remain to be settled before the monarch can retire in a step unprecedented for two centuries.

Japanese law does not currently allow an emperor to give up the throne, but Akihito, 83, who has had heart surgery and prostate cancer treatment, said in rare public remarks last August he feared age might make it hard to fulfil his duties.

A panel of experts is expected on Monday to indicate a preference for a special law to allow Emperor Akihito to retire, most probably by the end of 2018.

Officials are looking at ancient precedents, since the last time an emperor abdicated was in 1817.