Australia has stepped in again to try to force some Chinese investors out of a rare earths mining firm, telling two parties that they will also need government approval before selling their holdings to ensure the shares aren't sold to any related parties.\n\nSix China-linked investors were told in May to sell their shares in Northern Minerals Ltd., but failed to do so, which led the government to freeze some of those holdings in July. The move signals growing scrutiny of foreign ownership in critical minerals.\n\nTwo of the companies have now been told that before they sell any shares they must get the approval of the Australian government to ensure that the sale isn't to a related party, Northern Minerals said in a stock exchange filing. The orders affect investors linked to China, a key geopolitical rival.