when you say spa..do you mean jacuzzi/hot tub or massages?
The hotel has a Jacuzzi / Whirlpool spa at the Pool deck for use by hotel guests. There are Day Spas located close by to the hotel if you are looking for a spa experience.
Spa pool / jacuzzi by the lap pool as well as a treatment based spa.
Get an answer from Hilton Brisbane staff and past guests.