ExGrunt
No, the Antipodean rules are the same. In Oz, any statement or disclosure made in the course of giving evidence to a BOI is not admissible against that witness in any civil or criminal proceedings in any Federal, State or Territory court or before a Service Tribunal except in proceedings by way of a prosecution for giving false testimony at the BOI.
Problem here is that administrative action (eg show cause why one should not be discharged) isn't subject to this provision.