Apex domains cannot have CNAME records.
Question and response
Question
dig sw.OZ.AU. NS
Answer
sw.OZ.AU. 5 NS ns4.he.net.
sw.OZ.AU. 5 NS ns.sw.OZ.AU.
sw.OZ.AU. 5 NS ns3.he.net.
sw.OZ.AU. 5 NS munnari.OZ.AU.
Authority
The response has no authority records.
Additional
ns.sw.oz.au. 5 A 203.31.96.3
ns3.he.net. 5 A 216.218.132.2
ns4.he.net. 5 A 216.66.1.2
munnari.oz.au. 5 A 202.29.151.3
ns.sw.oz.au. 5 AAAA 2403:5812:c2f1:0:0:0:1:53
ns3.he.net. 5 AAAA 2001:470:300:0:0:0:0:2
ns4.he.net. 5 AAAA 2001:470:400:0:0:0:0:2
munnari.oz.au. 5 AAAA 2001:3c8:9007:1:0:0:0:21
munnari.oz.au. 5 AAAA 2001:3c8:9009:181:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0