A Chinese nuclear physicist whose research was key to the country's development of the hydrogen bomb and whose identity was a state secret for decades was awarded its top science prize Friday, state media reported.

President Xi Jinping presented the State Supreme Science and Technology Award to Yu Min, 89, at an annual ceremony honouring China's leading scientists and accomplishments in research, the official Xinhua news agency reported.

China joined the nuclear club in 1964 with a successful atomic test at its Lop Nur facility in the far western region of Xinjiang, and subsequently detonated its first hydrogen bomb in 1967.

Besides the hydrogen device, Yu also contributed to "miniaturisation of nuclear weapons, technological breakthroughs in the neutron bomb, and filled the nation's void in the theory of atomic nucleus", Xinhua said.

The China Youth Daily reported that Yu's name was a secret for 30 years and was only declassified in 1988.

Yu began working as a researcher at the Chinese Academy of Sciences in 1951, studying the theory of nuclear weapons, according to Cultural China, an official website.

He "solved a series of problems concerning thermal nuclear physics related to H-bomb tests", it said.

"Since the 1970s, he has been a pioneer and propellant of a number of high-tech research projects, which has played an important role," it added.

China's nuclear development was spearheaded by several key scientists, including Qian Xuesen, the man widely regarded as the father of China's nuclear missile and space programmes.

Qian, who died in 2009 at the age of 98, was born in China and studied at the Massachusetts Institute of Technology and the California Institute of Technology, or Caltech, in the United States.

He later served as director of the Jet Propulsion Laboratory at Caltech, but was accused of harbouring Communist sympathies and detained, though never charged with espionage.

Qian was returned to China in 1955, six years after the establishment of the People's Republic, in a negotiated exchange for American pilots shot down by the Chinese during the Korean War, and subsequently worked for the defence ministry.