There were over 100 of them with the Flam-backed Fiddler Crab. They are much smaller but have the same characteristics, as they waved around their enlarged claw similar to Fiddler Crabs
This specimen certainly looks like the Wait-a-While palm (aka lawyer vine) Calamus muelleri, but the distribution range of southern Qld/Northern NSW listed for this species doesn't fit. Is it a different species?