Tinnies is correct. There was a time, during the 70s, when they were also called "tubes" (or to use the phonetic spelling - "choobs"), during the time of a film about an ocker Aussie on safari in London called "The Adventures of Barry Mackenzie" starring Barry Croker (for the UK readers he was the singer of the original "Neighbours" TV show theme!). Not quite the advertisement for our country that I'd endorse, but an exposé of the chundering (under)belly of Aus culture.

BTW the collective noun for a carton of 24, or more recently 30, tinnies is a "slab"; as in "Give us a slab of VB, mate". We also have beer in 375ml (13 oz for the Americans) bottles called stubbies, and 750ml bottles which are referred to as longnecks. I had a friend who could drink a case (12) of longnecks and a half-bottle of Southern Comfort before dinner - an iron constitution (and a spongey liver).