Not Leioproctus as I thought, Anna. Michael thinks it is Lasioglossum (Parasphecodes) musicum - https://www.padil.gov.au/pollinators/pest/138333 Not seen in this region before, and not on the species list. I will try to get it added.
@PeterA - thank you. I originally thought the yellow on the shoulders must be pollen and wondered why it was only collecting there but now see that L. musicum has short sparse hair tufts that look similar