Net migration saw the largest ever drop on an annual basis in the year ended March 2021, Stats NZ says.
Net migration was provisionally estimated at 6600 in the year ended March 2021 compared with 91,900 in the year ended March 2020 - a drop of 85,400.
This latest data records the first full year of closed borders.
Net migration in the previous year (ended March 2020) was the highest ever.
The record migration gain for that year reflected the huge surge in arrivals through January and February 2020, as the pandemic drove Kiwis home from abroad.
Covid-19-related border and travel restrictions have resulted in record annual falls in both migrant arrivals and migrant departures.
"On an annual basis, these are the lowest numbers for migrant arrivals since 1986, and for migrant departures since 1969," Stats NZ population indicators manager Tehseen Islam said.
"However, we still have a net migration gain as migrant arrivals exceed migrant departures."
Provisionally, a net gain of 15,500 New Zealand citizens was partly offset by a net loss of 8900 non-New Zealand citizens in the year ended March 2021.
"Historically, New Zealand has had an annual net migration loss of New Zealand citizens and an annual net migration gain of non-New Zealand citizens, but Covid-19-related travel and border restrictions have reversed this pattern," Islam said.
"On an annual basis, migration estimates indicate a provisional net gain of New Zealand citizens since December 2019".
The net gain in New Zealand citizens in the year ended March 2021 is mostly due to fewer New Zealand citizens departing overseas, relative to those arriving.
As would be expected with the numbers limited by the travel restrictions and MIQ process, total arrivals and departures across the New Zealand border also saw record annual falls in the year ended March 2021.
There were 319,700 border crossings in the year ended March 2021, made up of 127,600 arrivals and 192,100 departures.
In contrast, in the year ended March 2020 there were 13.6 million border crossings, made up of 6.8 million arrivals and 6.8 million departures.
Border crossings include all arrivals and departures, either for short-term trips or longer-term, and by people living overseas or in New Zealand.
The numbers reflecting the full year of hard border closures may represent a low point for the pandemic.
"Provisional data from April 2021 have shown an increase in arrivals and departures with the opening of two-way quarantine-free travel with Australia," Islam said.