A near three-fold explosion in unpaid GST debt in the past six years is fuelling a surge in owed taxes to close to $50 billion at the same time the Tax Office has been struggling to control a $4.6 billion wave of fraudulent GST refund claims ignited via the viral spread of the scam on TikTok.

Collectable tax debt has more than doubled since 2017 from $20.9 billion to an estimated $50 billion, budget papers reveal. The biggest part of that surge has been GST debt, which went from $11.3 billion to $27.3 billion as of June 30, 2022, and is expected to rise to more than $30 billion in yet to be released ATO accounts. The debt represents tax bills that are uncontested but which the ATO has not been able to raise.