I don't know if this is an unadvertised deal but it's pretty decent when compared with historical prices for the travel period in question (and I assume there's similar deals from Perth and Melbourne as usual…). There's even a $169 SYD-DPS flight leaving on the 21st of January (but many more in Feb, Mar etc).
NB Since I couldn't find the deal advertised I have no idea of any details.
link to deal doesn't work…