You don't need to provide the written evidence with your tax return, but you must retain the original documents because we may need to see them at a later date.
Generally, you must keep records for five years after you prepared or obtained them, or after you completed the relevant transactions or acts, whichever is later.
We may generally amend an income tax assessment for an income year within two years of issuing the notice of assessment for that year in the case of individuals and very small businesses, or four years for other taxpayers.
This period of review may be extended by an order of the Federal Court of Australia or with your consent. Where this occurs, you must keep your records for five years or to the end of the period during which the assessment may be amended, whichever is later.
The period of review may also be extended by the effect of special amendment rules that allow an assessment to be amended within four years of a payment of foreign income tax or an increase or decrease in the tax paid.
You do not need to keep records where the Commissioner of Taxation has notified you that they are not required, or where your company has gone into liquidation and been finally dissolved.