AMSA is a member State of the Tokyo Memorandum of Understanding on Port State Control (Tokyo MOU). Both recent (2022 onwards) and historical detention information for ships in Australian ports, and the ports of foreign countries who are also member states, is published on the Tokyo MOU website.
You can access a ship's regional inspection history for free by visiting the Port State Control (PSC) database on the Tokyo MOU website.
The Tokyo MOU also publishes specific monthly detention lists which you can view for free here.
AMSA no longer publishes static information on ship detentions on its website, this information is freely available and searchable on the Tokyo MOU website which is considered to be the primary source for this information.