Union Bank of Australasia, Pitt and Hunter Streets, Sydney, c1890. The Union Bank of Australia operated between 1837 and 1951 (known as the Union Bank of Australia Limited from 1880). The bank acquired the Bank of South Australia in 1892. By its centenary in 1937, it had 267 branches and agencies through Australia and New Zealand. Union merged with the Bank of Australasia to form the Australia and New Zealand Bank Limited in 1951.