Pioneering composer and green activist Ryuichi Sakamoto, whose score for "The Last Emperor" scooped an Oscar and a Grammy, has died aged 71 after his second cancer diagnosis.

Having shot to fame in the 1970s with the influential Japanese group Yellow Magic Orchestra, Sakamoto's electronic innovations helped lay the foundations for synth-pop, house music and hip-hop.

But he was perhaps best known for his film soundtracks, including for the World War II drama "Merry Christmas, Mr Lawrence", in which he also acted opposite his friend David Bowie as a prisoner-of-war camp commandant.

The hauntingly catchy track "Forbidden Colours" from the 1983 film, with vocals by David Sylvian, became a global hit for Sakamoto, who also collaborated with Thomas Dolby and punk legend Iggy Pop in the 80s.

Sakamoto went on to win an Academy Award with his score for the 1987 period epic "The Last Emperor", directed by Bernardo Bertolucci, which tells the story of China's last emperor Puyi.

He lived in New York for decades, but his prolific career made him a huge star in his home country, where he was renowned for his strident anti-nuclear campaigning.

Despite his recent ill health – he survived throat cancer in 2014 – Sakamoto continued to win acclaim for his work, including the score for Alejandro Gonzalez Inarritu's 2015 film "The Revenant".

In early 2021, the musician said he was undergoing treatment for rectal cancer.

His management team announced Sunday that he died on March 28th, and a funeral was held for close family only, at his request.

"We would like to share one of Sakamoto's favourite quotes: 'Ars longa, vita brevis. Art is long, life is short," the team said in a statement. (AFP)