These are pages that help readers distinguish between pages that could have the same name. Most are created (and automatically listed here) by having template:disambig applied to them, at either the top or the bottom. They should all have links to the likely target pages with a very brief description where any page name is not self-explanatory.
Where a name - such as Christchurch - is so dominant in New Zealand speech and writing that no other use of the word is significant, the article with that name may just refer at the top to other uses; if they would take more than a few lines to cover, link to a separate page called "Name (disambiguation)", and make it a disambiguation page. See, for example, Hamilton (disambiguation).