Self-assessment and the period of review
Under the self-assessment system, we generally accept the taxpayer’s assessment of their tax liability as presented in their income tax return or other return.
However, we may later review and audit the return if this is warranted by further information or analysis, and amend the assessment if we discover an error.
In most circumstances, the tax law puts a time limit on the period in which we can amend a tax assessment. We may amend an income tax assessment up to two years (or four years for taxpayers with more complex tax affairs) after tax becomes due and payable on that assessment. Where anti-avoidance provisions of the tax law apply, the period is four years.
However, in a case where an opinion of fraud or evasion is formed, there is no time limit on us to amend an assessment.