@AlisonMilton : Those eggs look rather regularly spaced. Both Anestia and Orgyia bothe lay eggs in a clumpy fashion. They could be from some other species with a flightless female, see http://lepidoptera.butterflyhouse.com.au/faqs/flightless.html. Can you take them into protective custody and see what hatches?
Hi Don, I went back to collect them but I suspect they have already hatched. There is an empty shell of an insect within the web of eggs, which I have not yet investigated.