Stats NZ is introducing monthly Consumers Price Index information in 2027.
The Consumers Price Index, or CPI, measures how the prices of goods and services bought by New Zealand households change over time. It is one of New Zealand’s most important economic measures and one of the main ways New Zealand measures inflation.
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The full CPI is currently published every three months. Publishing CPI information monthly gives households, businesses, government and customers, like The Reserve Bank of New Zealand, a more up-to-date view of changing prices and support better-informed decisions.
As part of this change, we are also modernising the systems, data and processes used to produce the CPI.
Pathway to monthly CPI
The move will happen in stages:
- Early 2027: Stats NZ will test the monthly production process internally.
- May 2027: We will publish a transitional report covering price changes in April.
- June 2027: We will publish a second transitional report covering price changes in May.
- July 2027: We will publish the first official monthly CPI release, covering June, alongside the June quarter CPI.
- August 2027 onward: Monthly CPI will become part of our regular publication schedule.
Helping customers prepare with transitional reports
CPI information is used widely across New Zealand. Moving from quarterly to monthly information is therefore a significant change for the people and organisations that use the CPI.
Before official monthly CPI publication begins, Stats NZ will publish two transitional reports. The first report will be published in May 2027 and cover price changes in April. The second will be published in June and cover price changes in May.
These reports will be publicly available on the Stats NZ website, with the supporting data available through our online data tool, Aotearoa Data Explorer.
The reports will include data produced through the new monthly process, along with monthly figures for the previous year so users can compare changes over time. Information about the data sources and methods will also be provided.
The reports will give customers time to:
- test how they access the data and use it in their systems
- become familiar with monthly price movements
- understand how the new information should be interpreted
- provide feedback before official monthly publication begins.
The transitional reports will contain unofficial monthly CPI information. They are an important step in testing the new process and helping users prepare, but they will not replace the official quarterly CPI measure.
The first official monthly CPI release will be published in July 2027 and will cover the June reference month.
Modernising how we produce the CPI
Moving to monthly CPI requires a major change to the way one of New Zealand’s most important economic measures is produced.
The headline CPI is built from hundreds of detailed price indexes and large volumes of information about the goods and services New Zealand households buy. In addition to the headline CPI figure, Stats NZ publishes almost 600 price index series. All of these will be available monthly.
Producing this information every month means collecting data more frequently, processing it within a much shorter timeframe, carrying out quality checks more quickly, and preparing the results for publication each month.
To achieve this, Stats NZ is modernising the full production process behind CPI, from how information is received and classified, through to analysis, quality assurance and publication.
Teams across data collection, statistical methods, technology, processing, publication and customer support are working together to design and test the new monthly system. This includes establishing new processes, training people and preparing for the faster rhythm of monthly production.
Changing how we collect price information
We currently collect price information through a mix of postal surveys, in-store collection, scanner data and automated online collection. The move to monthly CPI is an opportunity to modernise and digitise these collection methods.
Stats NZ is increasing the use of information supplied directly by businesses and other organisations.
This includes point-of-sale or scanner data, which records prices and sales when products are bought. It provides information about the prices people pay throughout the month, including the effect of specials and changes in the products people choose.
Most monthly CPI information is expected to come directly from businesses. This will be supported by specialist datasets, automated online collection and targeted online surveys where suitable information is not available in another way.
Establishing these data supplies involves working with a large number of businesses. In some cases, businesses need to change their own systems so information can be supplied regularly and securely.
By setting up automated digital collection, Stats NZ can receive information more often without increasing the ongoing reporting burden on businesses.
Building new systems and methods
Monthly CPI is being built on modern, cloud-based technology.
New systems are being developed to receive information from different sources, process and analyse it, monitor its quality and publish the results through the Stats NZ website and Aotearoa Data Explorer.
Stats NZ is also reviewing the methods used for areas where monthly production requires a different approach. These include clothing, newly built housing, local authority rates, insurance, weighted average prices and seasonal adjustment.
For example, products and prices in areas such as clothing can change quickly. New methods and more detailed information are needed to identify products correctly and measure price movements reliably.
Almost all CPI series currently published quarterly are expected to also be available monthly. Some series require more work before their availability can be confirmed.
What happens to quarterly CPI?
Stats NZ will continue publishing quarterly CPI alongside the new monthly information.
Quarterly indexes will be produced using the monthly indexes and will continue to be available for people and organisations that rely on them.
The inflation rate based on quarterly CPI will remain New Zealand’s official measure of inflation until the Government Statistician announces otherwise.
Read Pathway to monthly CPI in 2027 announced.
