gazza - this information is taken from the NSW DPI 2012 Saltwater Fishing Guide:
When do I need to pay?
When you are fishing in NSW waters, both fresh and saltwater, you are required by law to carry a receipt showing the payment of the NSW Recreational Fishing Fee. This applies when line fishing (rod or hand line); spear fishing; bait collecting or when collecting
invertebrates using methods such as hand gathering, digging, pumping, trapping and prawn netting.
Exemptions:
Persons under the age of 18.
An adult assisting persons under the ageof 18 to take fish using a single rod per child or to take prawns using a single dip orscoop net per child.
A person fishing in a private dam with a surface area of two hectares or less.
An Aboriginal person.
this guide is available from here if you want a refresher: http://www.dpi.nsw.gov.au/fisheries/recreational/publications/fishing-guides2/guide