Malaysian media reported the newly-elected coalition government will shortly begin a three month evaluation of the company's rare earths processing operations in the province of Kuantan.
Until now, the Australian miner had been advancing exploration projects in Latin America focused mainly on gold, but with significant exposure to copper, molybdenum and zinc.
The proposed tax, to be applied on the nominal value of extracted metals, would affect copper miners that produce more than 12,000 tonnes of the metal and those extracting 50,000 tonnes of lithium a year.
Partners may lose their right to develop the Mt Holland lithium project after a recommendation by a unit of the West Australian government that regulates mining leases.