Kazuo Inamori, the founder of Japanese electronics maker Kyocera and telecoms group KDDI, has died aged 90, according to Agence France Presse.

He died "of old age" at his Kyoto home on Aug 24 and a family funeral has since been held, Kyocera said in a statement.

Japan's government convinced Inamori to come out of retirement in 2010 to head Japan Airlines (JAL) after the ailing carrier filed for bankruptcy.

The businessman -- who was 78 at the time -- said he was a "complete amateur" in the transport industry, but promised to "do my best".

His overhaul was successful and JAL shares were relisted on the stock exchange in 2012, less than three years after the airline was forced to delist.

Kyocera said it planned to hold a separate memorial for Inamori but details had not yet been decided.