My daughter (21 months) is having the same issue tonight. I'm not in Australia, but rather Reno, NV, USA. She did not have a cold or any other symptoms, then suddenly tonight she started throwing up and there was more mucus in her vomit than you could squeeze out of 1000 slugs... I've called the nurse hotline, my mother (a nurse practitioner) and left a message for her doctor - I will repost if I hear anything useful).
ms