China could cut rare earth exports by up to 30 per cent next year, state media said on Tuesday, in a move that will heighten global concerns about the country’s monopoly over the critical minerals.

China produces 97 per cent of the world’s rare earths – 17 elements vital to technological products as diverse as wind turbines, car batteries and sophisticated radar systems – a dominance that has become increasingly controversial as the government has steadily reduced export quotas for the minerals.

The report in China Daily – a state-run, English-language newspaper – comes just a few days after the US trade representative’s office announced it would investigate Beijing’s green technology sector to determine whether government support is in violation of China’s commitments to the World Trade Organisation.