The revered 82-year-old emperor's comments came in his second-ever televised address to the public.

While he did not use the word "abdicate", he strongly indicated that he wishes to hand over his duties.

PM Shinzo Abe said the government would "robustly" discuss the legal changes required for that to happen.

In 10-minute pre-recorded message, Emperor Akihito said he hoped the duties of the emperor as a symbol of the state could continue steadily without any breaks.

"I am worried that it may become difficult for me to carry out my duties as the symbol of the state with my whole being as I have done until now," he said.

He said one possibility when an emperor could not fulfil his duties because of age or illness was that a regency could be established. However, even in that case the emperor continued to be the emperor till the end of his life, he said.

There is no legal provision for abdication in Japanese law. A change in law would be required to allow the emperor to stand down.

Under the constitution the emperor is not allowed to have political powers, so saying more overtly that he wished to abdicate would be seen as interfering in politics.

Akihito has been on the throne in Japan since the death of his father, Hirohito, in 1989.

Opinion polls have indicated the Japanese public would widely support his decision to stand down.

(BBC News)