Australia still maintains a privilege against self-incrimination in criminal matters. Although this privilege can be abrogated in certain circumstances, the law holds this privilege as a paramount right of defendants. As professional criminal lawyers will tell you, It specifically includes the right to not make a statement and/or to not give evidence on your own behalf.
That works fine for the defendant who has been arrested and charged on the complaint of someone else, but what about where the defendant has previously been investigated by a professional body or commission of inquiry and was compelled by law to disclose documents, answer questions; and is now arrested and charged for the same conduct that was the subject of the inquiry?
The defendant has effectively lost their right to silence and more particularly was not cautioned about the effective waiver of their rights at the time of the inquiry or investigation.