Undisputed debts to the Australian Taxation Office increased by 77.6 per cent since 2016-17, with a review by the independent watchdog finding the majority is owed by a small number of taxpayers.

Inspector-General of Taxation and Tax Ombudsman Karen Payne launched an investigation into the ATO’s growing $45 billion debt book in late 2019, after a $7 billion increase in uncollected, undisputed tax debts.