The first comment that must be made is that the American Staffordshire Terrier is NOT an American Pit Bull Terrier. Although their origins are the same - the two are entirely separate breeds, and they must not be confused with each other.
The Pit Bull is not recognised as a pure bred dog by the ANKC (Australian National Kennel Club) and is banned from further importation into Australia. The Breed is also not recognised by the main controlling body for purebred dogs in the United States the AKC (American Kennel Club). The UKC (United Kennel Club) in the United States does however recognise Pitbulls. The UKC is not affiliated with ANKC or the AKC.
The American Staffordshire Terrier or Am Staff as it is commonly known, was officially recognised in 1936 by the American Kennel Club.
The first Amstaff arrived in Australia in 1986 with the breeds popularity slowly increased. Some believe that the bred in a large version of the Staffordshire Bull Terrier. If you have owned both breed you would come to realise that this is far from correct. The Am Staff does have its similarities to the Stafford but they are definitely not a larger version of the Stafford.