About this item

Issue date:
20 April 2023
Corporate Authors:
Health Information Standards Organisation (HISO), Health New Zealand | Te Whatu Ora
Document date:
20 April 2023
Health IT, Health system
Copyright status:

Copyright Held by Non-Crown Party

978-1-99-110036-8 (online)


This document presents a standard data set specification for the collection and representation of personal identity, demographic and digital account information for patients and consumers of health and disability services.

This standard pertains to the data content of the National Health Index (NHI) and My Health Account systems operated by the Ministry of Health, and to all patient management systems, clinical information systems and consumer health platforms used in Aotearoa New Zealand.

2023 revision of the standard

The latest revision of this standard includes an update to the check digit algorithm used for the new NHI numbering format. This update was made to mitigate an unacceptable risk of character substitution detection failures that were identified with the former approach. To address this, we have changed the check digit algorithm to use a modulus 23 operator, rather than a modulus 24 operator. This change remediates the character substitution failure concerns.

The update also announces 1 October 2025 as the date from which all new NHI numbers issued will be in the new format.

This standard is a living document and updates will continue to be made as new data requirements arise in the health and disability system and as further all-of-government mandated data standards for personal information are introduced.

For more information or to provide feedback please email standards@health.govt.nz.