Police are only allowed search you at a New South Wales music festival if they have a reasonable suspicion you possess drugs or other illegal or dangerous items. This requires more than just a positive indication by a sniffer dog.
You can only be strip searched if police reasonably suspect this is necessary due to the seriousness and urgency of the situation. The search must be undertaken in a private place by officers of the same sex who cannot touch you. You cannot be required to remove more clothing than necessary and a cavity search not permitted.
If you are asked to consent to a search, always politely refuse as informed consent will make an otherwise unlawful search, lawful.
You will only need to provide your identification if you are under arrest, can assist in the investigation of a serious offence or are under 18 and suspected of possessing alcohol in a public place.
You have the right to remain silent and should always exercise that right.