Hi,
Thanks to those who have pointed out that "organisation" is the only
word affected by this problem. Similar words, including its own
variants ("organised", "organiser"), are accepted by Word as Australian
spellings. The Commonwealth Style Guide lists "organisation" as the
preferred spelling for official publications and names (e.g. I'm pretty
sure CSIRO, ANSTO, DSTO, ASIO and DIO are all spelt with "Organisation"
in the legislation). Newspapers (including Craig's) seem to use
"organisation" too. Since "organisation" is also the expected spelling
in the higher-education and academic settings, one must use a "custom
dictionary" to overcome the problem.
Apparently, "organization" is predominant in some commercial settings
and in recent documents from government departments. I wonder if this is
*because of* the Word spell checker?! All other electronic dictionaries
I could find (including Apple's and aspell) prefer "organisation".