New Zealand Coding Conventions

Morbidity data is collected in New Zealand using The International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM), The Australian Classification of Health Interventions (ACHI) and The Australian Coding Standards (ACS).

The rules and conventions of ICD-10-AM/ACHI/ACS govern clinical coding practice and underpin consistency and accuracy of clinical coded information submitted to the National Collection – National Minimum Dataset.

A New Zealand Coding Convention is an additional requirement that clinical coders are required to follow. The coding conventions are developed and defined by the Ministry of Health in collaboration with relevant stakeholder groups.

New Zealand Coding Conventions
Australian Coding Standard (ACS) New Zealand Coding Convention (NZCC)
ACS 0029 Coding of Contracted Procedures
This standard relates to hospital treatment being carried out under contracting or subcontracting arrangements between two hospitals. The standard states ‘all procedures carried out under the contract are to be recorded and coded in both hospitals. The hospital not carrying out the procedure should flag the appropriate code’. However, the standard does say 'clinical coders should be familiar with their respective state/territory methods of reporting this information'.

In New Zealand only one hospital is to record and code the treatment provided under the contract arrangement and report to the National Minimum Dataset (NMDS). Where the hospital is a private hospital, it is preferred that the public hospital reports the event. However, the contract arrangement should specify the hospital that will be responsible for reporting the event to the NMDS.

Contracted event records must be reported to the NMDS with the appropriate agency, facility and funding agency codes and meet the 21-day reporting requirement.

Refer to the New New Zealand Casemix Framework for Publicly Funded Hospitals, WIESNZ21 Methodology 2021/22 v1.2 June 2021, 5.2.38 Designated Hospital for Casemix Revenue
Procedures performed at another hospital during an inpatient episode of care (transfers) Same day procedures performed at another hospital during an inpatient episode of care (transfers) may be reported to either NNPAC or NMDS but not both collections, as this would result in duplicate reporting.  This is a risk because it will affect Inter District Flow (IDF) funding for the DHBs and will overestimate the volume of activity occurring across the sector. See reporting guidelines below:


  • Each hospital will only report to the national collections the service/treatment they provide to the patient. Do not report the service/treatment provided by another public hospital/DHB (they will do their own reporting)
  • If a patient is transferred (not discharged) during an inpatient episode of care to a private facility for investigations/treatment and transfers back to the DHB the same day, the DHB should report the procedure(s) performed at the private facility in the DHB inpatient episode of care in accordance with the Australian Coding Standards (ACS).
ACS 0032 Allied Health Interventions There is no mandatory requirement in New Zealand to report Allied Health Interventions to the National Minimum Dataset (NMDS). Therefore, coding and reporting Allied Health Interventions as per ACS 0032 to the NMDS is optional.
ACS 0233 Morphology Reporting morphology to the National Minimum Dataset (NMDS) is not a mandatory requirement in New Zealand. Morphology information is collected directly by the New Zealand Cancer Registry (NZCR). Therefore, coding and reporting morphology as per ACS 0233 to the NMDS is optional.
ACS 0503 Drug, Alcohol and Tobacco Use Disorders The New Zealand Coding Convention to assign ICD-10-AM code Z71.6 Counselling for tobacco use disorder relates to the reporting requirement previously aligned to the Health Target ‘Better help for smokers to quit’. This reporting requirement is now aligned with the DHB Non-Financial Monitoring Framework and Performance Measures ‘Better help for smokers to quit in public hospitals’.

For more information, read New Zealand Convention on Counselling for Tobacco Use Disorder.
ACS 0534 Specific interventions related to mental health care services This coding standard refers to specific interventions related to mental health care services.  The standard states:
"For admitted episodes of care it is not mandatory to assign code(s) for mental health care interventions with the exception of electroconvulsive therapy. However their use is encouraged in specialist mental health care facilities and units to better represent care provided to these patients. It should also be noted that these interventions are not exclusive to mental health and may be assigned outside of this context."

Coding of the mental health interventions listed in the coding standard has been discussed with the Ministry's Director of Mental Health and the Principal Advisor of Mental Health, and the decision is that there is no requirement for New Zealand to code these mental health interventions listed in ACS 0534 for inpatient episodes of care. Therefore, coding and reporting mental health care interventions listed in ACS 0534 is optional.

As per the ACS 0533 Electroconvulsive therapy (ECT) will continue to be coded.

ACS 2001
External Cause Code Use and Sequencing
Z03.6 Observation for suspected toxic effect from ingested substance requires the assignment of an external cause to identify the specific substance, place of occurrence and activity codes. This is a mandatory requirement in New Zealand as specified in the NMDS Data Dictionary.
Back to top