Fiberplex by Protexin is a pro-and prebiotic paste for rabbits and small rodents, from what I can see, they have an Aussie distributor. http://www.protexin.com/worldwide-distributors/2/australia It’s a paste that helps get the tummy in order for small pets. My vet clinic sells it but I have been fortunate enough never to have had to use it. It is a reputable brand though, and I have used the probiotic paste they make for dogs with my dog when her tummy has been out of order.
Critical Care has an Aussie equivalent called CrittaCare, that I know some Aussie members here use/have used with their sick bunnies.
There is also a yest-supplement called Anima Strath that can be given to small animals. We have an Indian member who’s recently started using it with her bunny. I’ve never tried it but it has the same type of yeast that the Fiberplex has. From what I can see, it’s sold in Australia.
Supplements for cats and dogs can be a bit problematic because of the differences in nutritional needs between carni/omnivores and herbivores. While fat is very useful for cats and dogs when you need to fatten them up, rabbits’ tummies are not “designed” to process a lot of dietary fat.