Apex domains cannot have CNAME records.
Question and response
Question
dig nsw.greens.org.au. NS
Answer
nsw.greens.org.au. 5 NS ns2.nsw.greens.org.au.
nsw.greens.org.au. 5 NS ns3.nsw.greens.org.au.
nsw.greens.org.au. 5 NS ns4.nsw.greens.org.au.
nsw.greens.org.au. 5 NS ns5.nsw.greens.org.au.
nsw.greens.org.au. 5 NS ns6.nsw.greens.org.au.
nsw.greens.org.au. 5 NS ns1.nsw.greens.org.au.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0