Eco store is in most coles and safeway/woolies stores. It's in a pale blue box with a black and white photo on the front of all their products. I think you can buy it online from Nurture Nappies, but it's probably easier and cheaper to look out for it on special at the supermarket. It's about $8 usually. You only need the smallest amount, so even in a front loader I reckon you wouldn't have much of a problem with it.

ETA Welcome PlonkeeMumma! May the fluff be with you!!