Japan's Emperor Akihito could possibly relinquish the throne at the end of April 2019, government sources said Tuesday, referring to a new candidate date for his expected abdication that emerged in addition to the previously reported likely date a month earlier.

The new candidate date for closing the current Heisei era surfaced as the government decided to hold an Imperial House Council meeting on Dec. 1 to discuss the abdication date.

Prime Minister Shinzo Abe, who will chair the council meeting, visited the Imperial Palace on Tuesday afternoon where he is believed to have reported the planned convention of the gathering to the emperor, sources close to the matter said.

Following the emperor's rare video message distributed in August 2016 in which he signaled his desire to retire, Japan's parliament enacted in June a law to allow the 83-year-old emperor to pass the throne to his elder son Crown Prince Naruhito in what would be Japan's first abdication in two centuries.

The one-off abdication law obliges the government to determine the abdication date under a government ordinance after convening a meeting of the Imperial House Council, which is composed of 10 members including the prime minister, the chief justice of the Supreme Court, the head of the Imperial Household Agency and two imperial family members.

The government was leaning toward setting the date of the emperor's expected abdication on March 31, 2019, to pass the throne to Crown Prince Naruhito the next day.

But since unified local elections are expected to be held in March or April 2019, the idea to set the abdication date on April 30 to have the crown prince to succeed the throne the next day has also become a possible option, the sources said.

As for the idea of setting the abdication date in December 2018, Imperial Household Agency officials have shown reluctance toward the idea as ceremonies to mark the imperial succession would coincide with important year-end and New Year imperial events.