Japanese fashion designer Issey Miyake, whose global career spanned more than half a century, has died aged 84, an employee at his office in Tokyo told AFP on Tuesday.

"He died on the evening of August 5," she said over the telephone, declining to be named and without giving further details of his death.

Miyake's funeral had already taken place, with "only relatives participating" in line with his wishes, and there were no plans for a public ceremony, she said.

Public broadcaster NHK and other Japanese media reported the news of his death.

Miyake was part of a wave of young Japanese designers who made their mark in Paris from the mid-1970s.

He pioneered high-tech, comfortable clothing, side-stepping the grandiosity of haute couture in favour of what he called simply "making things".

Born in Hiroshima in 1938, Miyake was just seven years old when the United States dropped an atomic bomb on the city in August 1945.

He survived the blast, which killed an estimated 140,000 people on impact and led to the end of the Second World War after the bombing of Nagasaki three days later.

He established the Miyake Design Studio in Tokyo in 1970, and soon afterwards opened his first Paris boutique.

By the 1980s, his career was in full swing as he experimented with materials from plastic to metal wire and even artisanal Japanese paper. (AFP)