Actually the Dutch first "discovered" Australia (W.A.) quite a few years earlier and named it New Holland. The first documented and undisputed European sighting of and landing on Australia was in March 1606, by the Dutch navigator Willem Janszoon aboard the Duyfken. He mapped Cape York and the Gulf of Carpentaria ... So 'Hallo' it would have been.
Courtesy of Wikipedia:
When Who Ship(s) Where
1606 Willem Janszoon Duyfken Gulf of Carpentaria, Cape York Peninsula (Queensland)
1616 Dirk Hartog Eendracht Shark Bay area, Western Australia
1619 Frederick de Houtman[11] and Jacob d'Edel Dordrecht and Amsterdam Sighted land near Perth, Western Australia
1623 Jan Carstensz[12] Pera and Arnhem Gulf of Carpentaria, Carpentier River
1627 François Thijssen[13] het Gulden Zeepaerdt 1800 km of the South coast (from Cape Leeuwin to Ceduna)
1642–1643 Abel Tasman Heemskerck and Zeehaen Van Diemen's Land, later called Tasmania
1696–1697 Willem de Vlamingh[14] Geelvink, Nyptangh and the Wezeltje Rottnest Island, Swan River, Dirk Hartog Island (Western Australia)
Guess they couldn't populate it with convicts like Britain could as so it's mostly gone un-noticed really. So saying it was "discovered" by Captain Cook in 1770 ... isn't 100%, correctly true, really at all, perhaps, maybe.
Kit_e