josephfeatherweight in Australia your Per Diems are not taxed, you don't even need to mention them in your Tax Return! Why? Because the Politicians get lots of them so they love it being this way and the bonus is that it works well for us
For example in a previous job I was away for 3 weeks at a time, per diems every day and that amounted to a fair amount which meant not only did I earn more but I avoided a tax bracket which helped too