I was going to mention no-see-ums, but the article identifies them as the US equivalent. That is a different family than Tabanidae that is represented by the horseflies and deerflies.So small you can barely see them. I think they're just a flying tooth.
Sandflies in Australia (Midges and Sandfly) - Sandflybites
Sandflies Australia: You will find sandflies on nearly all beaches of Australia. STOP SANDFLIES NOW: Prevent, treat, heal – Real tips from real travellerswww.sandflybites.com
We have a number of different species and groups of biting flies, but I don't recall having encountered no-see-ums much. Those damned horseflies land right on the center of your back, often just out of range of where you can reach. But they are slow and clumsy and you can still get a chance to off them. The bite is like having a pencil stabbed into your back.