The US, European Union and Mexico have asked for a World Trade Organisation dispute panel to investigate Chinese restrictions on exports of specialised raw materials used in industry.

The move is the latest indication that the global slowdown is leading to greater international action against China's trade policies.

The request to the WTO claims that China's restraints on exports of bauxite, magnesium and other raw materials, which are used to make steel, aluminium and some chemicals, are driving up the price of those end products.

Australia has also become entangled in a trade dispute with China, its biggest trading partner, after it imposed an interim dumping duty of 16 per cent on Chinese exports of aluminium extrusion products.

The new complaints come ahead of the first visit to China of Barack Obama, US president, later this month when he is expected to raise trade issues and press China to allow its currency to appreciate.

The Obama administration has already imposed tariffs of 35 per cent on imports of Chinese tyres, prompting Beijing to announce a probe into US exports of poultry, cars and car parts.

Amid fears that the series of measures and counter-measures could lead to a trade war, the US and China had appeared last week to strike a conciliatory note. At a trade summit in the Chinese city of Hangzhou, they resolved outstanding US complaints over imports of pork and wind power equipment.

China is the leading extractor of a number of specialised raw materials widely used in industry, of which the EU imported €4.5bn last year. Its trading partners have complained for several years about restrictions on these products that include export duties in some cases of 15 per cent and other bureaucratic obstacles.

“China's restrictions on raw materials continue to distort competition and increase global prices, making conditions for our companies even more difficult in this economic climate,” said Catherine Ashton, the EU's trade commissioner.

China's ministry of commerce said the purpose of the restrictions was to protect the environment by raising the cost of resource extraction.

“The overseas demand for those products has been shrinking, so it is an exaggeration to say that China's measure would affect the EU or US steel industry's recovery from the financial crisis,” it said.