Japan's Emperor Akihito reads a message for recording at the Imperial Palace in Tokyo. File picture: Imperial Household Agency of Japan via AP

Tokyo - Japanese Emperor Akihito is to relinquish the Chrysanthemum throne on Tuesday, ending his 30-year reign in the country's first abdication in about 200 years.

The 85-year-old emperor, dressed in traditional robes, performed his last rituals at the Imperial Palace in central Tokyo, reporting his abdication to his ancestors.

The government is scheduled to hold a ceremony at the palace at 5 pm (0800 GMT) to be attended by about 300 people, including other imperial family members, Prime Minister Shinzo Abe and cabinet ministers.

Emperor Akihito will formally hand over the throne to his eldest son Crown Prince Naruhito at midnight Tuesday.

US President Donald Trump sent a message to the emperor and Empress Michiko on the imperial couple's final day on the throne.

"On behalf of the American people, the first lady and I offer our heartfelt appreciation" to the couple, the president said in a statement.

Trump and his wife Melania met the couple when they visited Japan in 2017.

The president and Melania will also hold a meeting with new Emperor Naruhito in May when they visit Japan as the country's first state guests after his enthronement.

Japan's Crown Prince Naruhito, in a car, leaves the Imperial Palace in Tokyo. Picture: Hiroko Harima/Kyodo News via AP

"Ever since ascending the throne as Emperor and to this day, I have spent my days praying for peace in the country and for the happiness of the people and thinking about my role as the symbol of the state," Akihito said at an event in February, marking the 30th anniversary of his accession to the throne.

"I have been able to fulfil my duties thanks to the people of Japan, whose symbol of unity I take pride and joy in being," he added.

The emperor and Empress Michiko will become emperor emeritus and empress emerita following the abdication, the Imperial Household Agency said.

The couple will not attend a second ceremony on Wednesday, which will mark 59-year-old Crown Prince Naruhito's ascendance to the throne.

The imperial succession will mark the beginning of a new era for Japan, which lays claim to the world's oldest monarchy.

Japan's Emperor Akihito leaves after a ritual to report his abdication to the throne, at the Imperial Palace in Tokyo. The 85-year-old Akihito ends his three-decade reign on Tuesday when he abdicates to his son Crown Prince Naruhito. Picture: Japan Pool via AP

The start of the new era "Reiwa" has given some Japanese people a market opportunity. Some are selling T-shirts bearing the word "Reiwa," others marking "Reiwa" chocolates, "Reiwa" candies, and "Reiwa" rice crackers.

The Japanese public will have a chance to meet the new emperor, his wife, Empress Masako, 55, and other imperial family members on Saturday, when they appear on a palace balcony, the imperial agency said.

In mid-March, Emperor Akihito kicked off a series of ceremonies and rituals for his abdication, including his travelling to the mausoleum of Japan's legendary first leader, Emperor Jimmu, in the western city of Kashihara.

On their last trip outside of Tokyo earlier this month, the emperor and the empress offered prayers at the Ise Jingu ancient Shinto shrine in central Japan. The shrine is dedicated to the sun goddess Amaterasu Omikami, the imperial family's ancestral deity.

A Japanese flag is held as people gather near Imperial Palace, back, in Tokyo. Picture: Eugene Hoshiko/AP

A week ago, the couple visited the tomb of Emperor Hirohito, Akihito's father, in the Musashino Imperial Graveyard in the western part of Tokyo.

Akihito assumed the throne on January 8, 1989, at the age of 55, following the death of Emperor Hirohito, in whose name Japan fought and lost World War II. 

In a rare video message in August 2016, Emperor Akihito indicated his desire to renounce the throne, citing concerns that his advanced age and frail health could prevent him from fulfilling his official duties as the symbol of the state.

Since the emperor does not hold any political authority, he cannot discuss abdication directly. Japan's parliament enacted one-off legislation in June 2017 allowing him to abdicate.

Japan's imperial family claims the longest hereditary lineage in the world, stretching back more than 2,600 years, according to the government. However, the existence of legendary figures such as Emperor Jimmu has been contested.

dpa