So checked the QF calculators page (Where Could I go) - oneway Y ex MEL-BNE is 12,000 points and $15.40 in charges.
"Brisbane
12,000*
QANTAS POINTS
EconomyTaxes, fees and carrier charges AU $15.40. ^"
But when booking is more like $32 in charges. No big deal really, but just booked 5 pax...