Firms handing back millions in coronavirus wage subsidies have sparked calls for an inquiry into corporate profits and executive bonuses linked to the $90 billion JobKeeper scheme.

Mineral sands miner Iluka Resources became the latest JobKeeper recipient to voluntarily pay back subsidies on Wednesday, after it recorded a recovery in key markets. The Perth-based company said it would return $13.6 million, cash it received after a big drop in zircon demand as COVID-19 took hold in China at the start of last year.