The Australian Taxpayers’ Charter states that the tax obligations of Australians is based on a system of voluntary compliance.

Read it for yourself.

Update 3-Aug-2010

The links have changed, and a new Taxpayers’ Charter has been published. This page has now been updated to reflect the new changes.

BEING COOPERATIVE (Page 17)
We prefer to work with you cooperatively, providing you with help to meet your
obligations voluntarily. However, if you are uncooperative or obstructive, we may need
to take firmer action. For example, we have formal access and information gathering
powers that we use if necessary. People who are obstructive may even be prosecuted.
We ask that you treat us with the same courtesy, consideration and respect we are
expected to give you. If we are subjected to rude or abusive behaviour, we may end
an interview or phone call.

The Australian Taxpayers’ Charter is available from the links below.

http://www.ato.gov.au/corporate/content.asp?doc=/content/63133.htm

http://www.ato.gov.au/content/downloads/cor63133_n2548.pdf

The previous version is shown below for archival purposes.

(Pre June 2010) Taxpayers’ Charter – what you need to know (NAT 2548) – Page 23.

06 Being cooperative in your dealings with us

The tax system is based on taxpayers complying with the tax laws voluntarily
and cooperating with us. This allows us to run the tax system at a relatively low
cost to the community and minimises unecessary intrusion into your affaisr and
those of third parties.

We prefer to work with you cooperatively, providing you with help to meet your
tax obligations voluntarily. However, if you are uncooperative or obstructive,
we may need to take firmer action. For example, we have formal access and
information gathering powers that we use if necessary. People who are
obstructive may even be prosecuted.

We ask that you treat tax officers with the same courtesy, consideration and
respect they are expected to give you. If tax officers are subjected to rude or
abusive behaviour they may end an interview or phone call.

Tax is Voluntary