Hi there Mutt. I think you will find most domestic jet airlines and regionals in Oz will have a 30 min fixed reserve, and a 10% variable reserve policy. The variable reserve can legally be used . Therefore you only have to land with the 30 min fixed reserve. Anything less than this constitutes a fuel emergency. As stated, this is based on a hold at 1,500 feet above the airfield. In VMC conditions, there is no requirement to carry alternate fuel, hence they don't.
If you want to see some pilots carry buckets of fuel around for no good reason, go to Europe. In some cases it is mind boggling.