Former coal billionaire Nathan Tinkler says the Australian government erred by allowing Swiss and Chinese-dominated companies to take too much control of the local thermal coal industry, and the severely depressed prices mean it is time for big cuts to supply and costs.

Mr Tinkler became Australia's youngest billionaire in 2011, thanks to well-timed investments in the coal sector, before a luxurious lifestyle led him to bankruptcy in 2016, which was later annulled in 2018.