The Ospreys' match with the touring Australians at Swansea's Liberty Stadium will be a 20,000 sell-out.
Swansea famously beat the touring Wallabies in 1992
The region have no more group tickets for the 1 November game, although a handful of single seats are still available for sale.
John Connolly's Wallabies fly to Britain this weekend, and Wednesday's match will be their opening fixture.
The game will be broadcast live on BBC Two Wales, 2W, Radio Wales, Radio Cymru and online.