Talk:Maori Rock Art
You have got a hard area to research remote form NZ libaries!
Have a look at http://www.nzarchaeology.org/cantotagsouth.htm - some links there that may help
Archaeopedia - look at the Fomison and Schoon pages
See if you can find Trotter and McCulloch http://catalogue.nla.gov.au/Record/72780 - it is the best starting point for this.
You might find some more on the JPS site http://www.jps.auckland.ac.nz/
http://epress.anu.edu.au/terra_australis/ta29/pdf/ch26.pdf is a goodie