You should lodge your outstanding tax returns as soon as possible and before the Australian Taxation Office takes any action to have you lodge these tax returns. Once they have begun any action, it could result in a court conviction. The ATO may charge a penalty of $110 for every 28 days that the return is outstanding.

The maximum penalty is $550 even if you are due a refund. In addition, the ATO will charge interest. This is called the General Interest Charge and is levied on any outstanding monies. The rate for the July to September 2009 quarter is 10.13%.