I don't think that this has been mentioned before on the forum.
The NSW Lands Dept has released certain mapping data as Open Data under the Creative Commons Attribution By Licence.
http://www.lpi.nsw.gov.au/mapping_and_i ... b_services
While this does include the NSW Topographic maps, it is the rasterised version. So if you want data off any specific layer (eg contour) you would have to manually derive it. Which you would be permitted to do since the CC BY 3.0 AU licence does permit you to
"Adapt — remix, transform, and build upon the material for any purpose, even commercially."
Also available is the NSW Imagery (aerial photos) data
See http://www.lpi.nsw.gov.au/mapping_and_i ... b_services for more info, and for other Open Data Web Services.