Hong Kong (CNN Business)The trade fight between China and Australia appears to be escalating, with Beijing reportedly placing new restrictions on imports of Australian coal.

Australian Trade Minister Simon Birmingham on Tuesday said he was " deeply troubled" by new reports in Chinese state media that the country's top economic planner has effectively banned certain coal imports from Australia. The Global Times, a state-run tabloid, reported last weekend that the country's National Development and Reform Commission has given power plants approval to buy overseas coal without restrictions — except from Australia.