John Simpson Kirkpatrick (normally just known as "Simpson") is quite a well known figure in Australian history. (Or at least he used to be; history teaching isn't quite what it once was.)
Attached to the 3rd Australian Field Ambulance during the landings at Gallipoli on 25 April 1915 Simpson, ably assisted by his donkey, carried water up to the troops on the line and carried wounded men back. The latter is portrayed in this sculpture. "The man with the donkey", as he was known by many who knew of him but not his name, was fatally wounded on 19 May 1915.
Someone has attached red poppies (a symbol of remembrance, particularly of World War I veterans) to the sculpture. Traditionally these are only worn around Remembrance Day (11 November) but these seem to be attached all year round here.
The (unintentional) slight "halo effect" above Simpson's head was more a by-product of the (intentional) back-lighting, but is interesting all the same.
The sculptor is Peter Corlett, who also created the sculptures of the Victorian premiers which can be seen in various shots in the A Day And A Bit In Bleak City gallery (particularly image (image 3464 and those following.) According to Corlett's own web site, this sculpture was done in 1988.