Emperor Akihito and his wife Empress Michiko pictured in Takaoka, Toyama, Japan

Emperor Akihito of Japan is expected to abdicate in 18 months, it was claimed yesterday.

It will be the first time a Japanese monarch has stepped down for 200 years.

Crown Prince Naruhito, 57, is expected to ascend the Chrysanthemum Throne in April 2019, after his 83-year-old father abdicates.

Akihito is said to be the 125th monarch to occupy the throne.

The first, Emperor Jimmu, is traditionally believed to have founded the Japanese monarchy upon his accession in 660BC.

The government is in the final stage of formalising the schedule, according to local media reports.

In June, Japan’s parliament passed a law allowing Akihito to abdicate and the government needs to hammer out the details including the timing.

Emperor Akihito's son Crown Prince Naruhito, 57, is expected to ascend the Chrysanthemum Throne in April 2019

But Yoshihide Suga, Japan’s chief cabinet secretary, denied the claims that an 18-month timescale has been drawn up.

‘We are not aware of the report and there is not such fact,’ he said.

‘We will do our best to carry out the emperor’s abdication smoothly.’

Akihito has had heart surgery and treatment for prostate cancer.

He said last year that he feared age might make it hard for him to fulfil his duties.