After losing two of his senators, Clive Palmer's recent string of bad luck has continued with the High Court tossing out a challenge to the now defunct carbon tax launched by one of his companies.

The High Court unanimously upheld the validity of former prime minister Julia Gillard's carbon tax, which Queensland Nickel attempted to argue discriminated between Western Australian nickel producers and Queensland refineries.

Mining magnate turned politician Clive Palmer. Credit:Rob Homer

Queensland Nickel's refinery is wholly owned by Clive Palmer and in 2012, Mr Palmer, who had not entered the Parliament at the time, claimed to have received legal advice that the carbon tax was unconstitutional.

Queensland Nickel argued the producers in WA processed a different kind of ore with a smaller greenhouse gas footprint, meaning it paid a higher carbon tax bill than its competitors.