Statistics NZ maintain a large number of public approved classifications. The page here http://www.stats.govt.nz/surveys_and_methods/methods/classifications-and-standards/classification-related-stats-standards.aspx provides a list of them. These are maintained in an internal database system. Excel extracts are made available for individual classifications. What would be useful is for either: a) an extract of all the public classification data in one go ( as one or more CSV files perhaps). This would simplify reuse b) a public web service for interaction Assuming b) is a large IT investment, then a) would be acceptable.

Standardising the use of existing classifications by 3rd parties, such as businesses, or even local authorities.
Allow the matching of data at different levels of the same classification.

Making it easier for 3rd parties to import and reuse the classification data in their data analysis and presentation