Tokyo (AFP) - Oscar-nominated Japanese anime director Isao Takahata, who co-founded the Studio Ghibli and was best known for his work Grave Of The Fireflies, has died aged 82, the studio said on Friday.

It is true "but we can't comment further as we are trying to confirm some facts around it", a Studio Ghibli spokeswoman told AFP.

Citing unnamed sources related to him, public broadcaster NHK said he had died at a Tokyo hospital after a recent bout of ill health.

Takahata's latest film, The Tale Of The Princess Kaguya, earned him an Academy nomination in 2014 for Best Animated Feature.

It was also selected for the Directors' Fortnight sidebar to the main competition at the 2014 Cannes Film Festival.

However, most consider the 1988 film Grave Of The Fireflies, a moving tale of two orphans during World War II, to be his best work.

Born in Mie prefecture in central Japan, Takahata started his career in animation at the Toei studio in 1959, where he met his long-term collaborator Hayao Miyazaki.

With Miyazaki, he co-founded in 1985 the Japanese animation Studio Ghibli, which went on to produce several blockbusters. The pair are often described by the media as friends and rivals at the same time.

Over a long and distinguished career, he produced around 20 films, including Only Yesterday (1991) and Pom Poko (1994).

He also produced the Miyazaki-directed 1984 film The Valley Of The Wind, a science fantasy adventure that describes the relationship between nature and human beings.

He is also well-known for the animation series Heidi, Girl Of The Alps and Lupin The Third.