Chinese factory output is likely to be contracting faster than bearish official data suggests, sparking warnings that power rationing across the world’s second-biggest economy could harm demand for a swath of Australian commodities.

The threat posed by Chinese power rationing to Australian alumina, bauxite, copper, zinc and lithium looms as the dark side of soaring prices for Australian coal and gas amid a global shortage that has plunged China and parts of Europe into an energy crisis.