This deal is originally for New Zealanders. That is why if you are in Australia, then only return ticket is on the deal. (Unless you want to pay for somebody to travel from NZ to OZ and back).
According to google 161NZD = 132AUD and 148NZD = 121AUD:
http://www.google.com.au/search?hl=en&q=161+nzd+in+aud
Details (prices are in NZD):
From Auckland to Economy Class Business Class
Sydney One Way $161 $541
Brisbane One Way $163 $543
Sydney Return $365 $1,125
Brisbane Return $368 $1,128
From
Christchurch to Economy Class Business Class
Sydney One Way $148 $528
Sydney Return $338 $1,098
The service on Emirates trans tasmanian flights is among the best in the world (hot food, free drinks, large comfy jet, etc) in my opinion.
PS. This is my first post here, so take it easy. ;o)
No melbourne flights but pretty good still, gets a positive from me for a first post!
Business class flights looks really tempting!