Rio Tinto has signalled the Albanese government’s spending on decarbonisation is inadequate, saying a tenfold increase was required alongside special treatment for its unionised aluminium smelters.

Labor has set aside $600 million for direct grants to help companies invest in technology to meet tougher emissions reductions due to come in under reforms to the safeguard mechanism, a figure Rio Tinto says should realistically be at least $6 billion over 10 years.