GOLD is indeed backed by physical gold, but is unhedged. What this means is that if the price of Gold rises, and the AUD rises as well (which historically occurs most of the time), then your performance will be reduced by the amount that the AUD rises.
For a hedged physically backed gold exposure, the only ETF on the ASX is QAU, which you may want to look at. The hedging takes out the risk of currency fluctuation on the performance of the ETF
