Criminal Code Act 1899

If the sentence was passed, or the process was issued, by a court having jurisdiction under any circumstances to pass such a sentence or to issue such process, or if the warrant was issued by a court or justice or other person having authority under any circumstances to issue such a warrant, it is immaterial whether the court or justice or person had or had not authority to pass the sentence or issue the process or warrant in the particular case; unless the person executing the same knows that the sentence or process or warrant was in fact passed or issued without authority.