I will be flying in to Ho Chi Minh airport - does anyone know if it is possible for Australians to get a V visa at the airport?
Austrians are not exempted from a Vietnam visa. You'd better get one in advance (at home or somewhere else) or a pre-arranged visa.
If you can get it in Australia then do so, otherwise you would have had to have already organised it to be waiting for you in HCMC airport. There are legitimate organisations that will do this for you - trick is to find one that is legit!

Have a look at this recent thread
Vietnam visa from Australia
It is very easy, a couple of days turnaround and all hassle removed!
Have a great trip :)