Former postal worker Jirouemon Kimura told city officials of his native Kyotango in western Japan that he was "extremely moved" when he learned he had become the world's oldest man following the death of a retired US railroad worker on April 14. "I heard the news and it is a great honour," he told the officials.

His secret is to eat sparingly, stopping when his stomach is about 80 per cent full, he says.

Kimura told local officials on his 113th birthday last year that his goal was to reach 120 and  he confirmed "that hasn't changed," Kyotango officials say.

City officials described him as alert and lucid as he sat upright and fielded their questions for 50 minutes.

Kimura fathered seven children and has 14 grandchildren, 25 great-grandchildren and 11 great-great-grandchildren, according to the city.

Kimura, who worked in the local post office for 40 years and then farmed until he was 90, now spends most of his time in bed, but is able to walk with a walker and always eats three meals a day, the city quoted family members as saying.

The Los Angeles-based Gerontology Research Group lists Kimura as the world's oldest man and Japan's Tanekichi Onishi, 111, as the second oldest. There are five women older than Kimura on the list, including two from Japan.

- Reuters