By Faith R. Short, Info resource from http://www.criminal-lawyers.com.au/criminal-law/offences/indecent-act-with-child-under-age-16
One of the possible defences an accused can use when charged with indecent act is consent. By consent, it means that the complainant and the accused freely agreed to do a sexual act.
In sexual offences, the prosecution must establish that there was no consent from the complainant and the accused was not aware of its absence. One situation where absence of consent may apply is when complainant was threatened with harm, or his or her judgement has been impaired by alcohol or drugs.
In indecent act with a child under the age of 16, the accused must also prove that there is reason to believe that the complainant is over 16 years of age.