All hops need a specific length of day in order to set cones (flowers) and without that they will not yield well (as you have noticed). If you are serious about growing hops in such a tropical location, you might like to consider ways to extend the 'daylight' hours for your hop plants by using artificial light.
There is no Australian hop variety that is 'better' at that latitude than USA varieties - and if anything I would have suggested Cluster and Chinook (which are Australian-grown American varieties anyway). All Australian commercial-hops are grown about 37 degrees (or further) south, and while some AHB members grow hops (with some success) in Brisbane QLD, that is about 27 degrees south.