International Migration

1860 – first reliable coverage of New Zealand's international arrivals and departures. Earlier data did not cover all of New Zealand's provinces.

April 1921 – arrival and departure cards are introduced. Passengers are split into three passenger types - overseas visitors, New Zealand-resident travellers, and permanent and long-term migrants.

1942–1945 – limited detailed data during WWII.

April 1975 – sampling of arrival and departure records begins. Some detail is only captured from a sample of arrival and departure cards, and statistics are produced by multiplying the results by the sample ratio.

April 1978 – detailed international travel and migration statistics for this month onwards are available in electronic format. Most earlier detail is only available in hard-copy reports.

July 1979 – sampling of permanent and long-term migrants ends, with detailed data now collected for every migrant.

September 1997 – the New Zealand Customs Service begins supplying Statistics New Zealand with passport and flight data electronically for all arrivals and departures. Statistics New Zealand holds a record for each passenger movement from this date. Some detail continues to be collected from arrival and departure cards for only a sample of passengers.

June 2004 – Statistics New Zealand begins using scanning and image-recognition technology to automatically capture most of the required information from arrival and departure cards.

July 2008 – the name "International Travel and Migration" is adopted, replacing "External Migration", which had been used since 1921. The new name better reflects that the statistics include short-term travellers as well as permanent and long-term migrants.

July 2013 – New simplified departure card is released. Some changes to arrival and departure information as a result.

August 2016 – New processing system is introduced (See 'Data Collection' 'International travel and migration processing system changes in August 2016' for more information).

May 2017 - Report describing the 12/16-month rule for classifying migrant status.

November 2018 - Removal of departure card from the New Zealand border and is replaced by smarter electronic systems.

January 2019 - International migration uses the outcomes-based measure. This is a new official measure estimated from the actual travel histories of people travelling in and out of New Zealand. It provides a more accurate measure of migration – a traveller is classified as a migrant based on their actual movements. This new measure replaces the previous migration measure (permanent and long-term (PLT) migration) which was estimated from travellers’ statements on arrival or departure cards – based on how long they intended to stay in New Zealand (or be away).

January 2019 - First release of the international migration data using the outcomes-based measure..

January 2019 - Separate International migration and International travel releases. Before January 2019, International migration and travel were published combined as one release.

March 2020 - New data on migrant departures to Australia. This is the first time Stats NZ has published figures showing migrant departures to Australia, since the end of traveller departure cards in November 2018.

March 2020 - Temporary release of regular border-crossing flow data to facilitate analysis of the COVID-19 international pandemic and impact on inbound and outbound tourism sectors.

International Migration

The outcomes-based measure of migration with provisional and final estimates is now the official way we measure migration in New Zealand. The results build on the outcomes-based measure of migration that was released from May 2017 and enabled the removal of the departure card.

The new approach uses passport data to link arrivals and departures and accurately measure how long people spend in, or out of, New Zealand after their initial border crossing. To classify a border crossing as a migrant movement, we need to observe up to 16 months of travel history.

With this new approach it takes 17 months before final migration estimates are available. To produce timely results, we use a statistical model to produce provisional migration estimates. Statistics produced using these provisional estimates have uncertainty for 16 months; after this time we can finalise the classification of all border crossings (according to the 12/16-month rule).

As new data becomes available, the provisional migration model has more information about the border crossings it is trying to estimate. So, with an extra month of data available, this causes shifts in the estimated number of migrant arrivals and migrant departures, and thus changes in the net migration estimates.

For example, the extra data will indicate travellers who have now departed New Zealand, or travellers who were away that have since returned to New Zealand.

Compared with total border crossings, the number of migrants is very small. Of every 50 people crossing our border, typically 49 are short-term movements and only 1 is a migrant arriving or departing.

The migration estimates become more certain after each subsequent month. For a typical month, 1 in 4 arrivals are classified with certainty for the first estimate after six weeks (after the end of the reference month). This increases to 9 in 10 after four months. The monthly revisions can therefore be expected to become relatively small after about five months, as we can calculate the duration of stay/absence more definitively.

Of the 14 million border crossings in the December 2018 year, 81 percent of border crossings were classified with certainty at the time of the first estimate in mid-February 2019. The remaining 19 percent represent 2.6 million border crossings, so a small change in classification can affect the migration estimates.

Customers therefore have a choice of using the most timely migration estimates which have more uncertainty, or waiting a few months until the migration estimates become more certain.

Outcomes-based and intentions-based measures compared

The previous migration measure (permanent and long-term (PLT) migration) was estimated from travellers’ statements on arrival or departure cards – based on how long they intended to stay in New Zealand (or be away). This intentions-based measure was timely; however, traveller behaviour was not always consistent with the stated intentions at their border crossing. This may be due to: circumstances changing, misunderstanding the questions on the traveller cards and incorrectly reporting their intentions, or deciding to extend their visa or stay/absence.

The outcomes-based measure is estimated from the actual travel histories of people travelling in and out of New Zealand. This provides a more accurate measure of migration – a traveller is classified as a migrant based on their actual movements.

The outcomes arrival and departure estimates are consistently higher than intentions PLT estimates.

The outcomes net migration estimates are sometimes higher, and sometimes lower, than intentions PLT estimates. In recent years, net migration using outcomes was lower than intentions.