Recently, the Archival Platform, a South African based website, announced its registry of South African archives – http://www.archivalplatform.org/registry/. It’s a great achievement and one they are justifiably proud of.
The Australian National Data Service has a number of institutions that have contributed data, but it is by no means comprehensive – http://researchdata.ands.org.au/search/#!/class=party/p=1/q=archives/ .
Internationally, the UK Register of Archives, and the collections available through A2A, provides an institutionally supported model for identifying archives – http://www.nationalarchives.gov.uk/nra/default.asp. Looking at the search options, it is clearly based on ISAAR CPF. Or there is the ArchivesGrid, via WorldCat and OCLC – http://beta.worldcat.org/archivegrid/. Based in the US, there are nonetheless an increasing number of Australian and other institutions sharing their details. American historians too, are adding details of various repositories to a central database – http://archiveswiki.historians.org/index.php/Main_Page
We had a similar registry through the Register of Australian Archives and Manuscripts, which is sadly no longer kept up to date. Similarly, the Cultural Collections Network is no longer supported, and so does not provide a simple, single way of finding cultural heritage institutions. Dr Mark Brogan, from Edith Cowan University, started a project with his students to revamp the Register (http://www.directoryasa.futureswest.com.au/), but there is still some way to go. Perhaps TROVE will become the de facto register?