I was so surprised by this post, I rang DOTAG in W.A to check. They confirmed that this Australian Commonwealth AG information is up-to-date , & is correct.
“This means, for example, that a person cannot marry their parent, grandparent, child, grandchild, brother or sister. However, (depending of course on the gender of the party) a person may marry their aunt or uncle, niece or nephew or ‘first’ cousin.”
Not only this, but the US, who I have in the past made rude comments about having backwards hillbilly states allowing cousins to marry, is the only Western country that specifically prohibits marriage between first cousins in some states.
I apologise, USA. Mind: blown / horrified