The history of New Zealand English is well attested. Previous studies focussed on the development of the New Zealand accent (Gordon et al. 2004) and are based on spoken data. Written data would enable linguists to study the emergence of standard New Zealand English (NZE) and differential change in this variety vis à vis British and American English. The present article discusses the requirements that such a diachronic corpus of written NZE should meet and presents a case study on the use of the progressive. The data from the Corpus of Early New Zealand English (CENZE) show that the frequency with which the progressive is currently used in NZE is a very recent development that is unlikely to be attributable to influence from Irish English (IrE) during the colonial period.