Fewer arrivals into New Zealand and increasing numbers emigrating have caused net inflows to fall to three-year lows.
September's net migration fell to 4640 while the annual inflow of people fell to 62,700, the lowest since October 2015, Westpac senior economist Satish Ranchhod said.
"The result leaves the trend decline in annual net migration firmly in place," he said.
There were 129,000 migrant arrivals, down by 2600, and 66,200 migrant departures, up by 5600, for the year ended September, compared with the same period last year.
Statistics New Zealand population insights senior manager Brooke Theyers said the increase in migrant departures and decrease in migrant arrivals both contributed to the lower net migration level.
"However, the increase in migrant departures had a greater effect as the change was larger, particularly for non-New Zealand citizens," she said in a statement.
Of the 66,200 migrant departures, more than half were New Zealand citizens, or 34,500. However, non-New Zealand citizens leaving the country rose to 31,800 over the 12 months, Theyers said.
ASB economist Mark Smith said the fewer arrivals and more departures were "cooling" net immigration.
"Encouragingly for labour market capacity, annual work visa numbers, 46,933, continue to set new record highs," he said.
He said annual departures firmed to 66,249 people, the highest since February 2014.
The pick-up in annual permanent and long-term departures was broad-based.
He noted the annual departures to Australia of 25,710 people was at its highest level since April 2015.
"That's likely as a result of the strengthening Australian labour market and higher wages on offer across the Tasman," Smith said.
Ranchhod said the annual inflow of people into the country had now fallen from a peak of 72,400 in 2017 to 62,700 now.
"While that's still high, it's the lowest level since October 2015. "We expect to see a further decline over the coming years," he said.
The biggest factor continuing to weigh on migration was departures of non-New Zealand citizens to areas other than Australia, which had remained high, he said.
"That's actually an echo of the increase in arrivals of those on temporary work and student visas that we saw in previous years," Ranchhod said.
Migrant arrivals on work visas increased by 2.5 per cent, or 1100 people, to 46,900 for the year ended September, Theyers said.
The different types of work visas catered to those on working holidays, seasonal workers or other working schemes. Those visa types were the most popular for permanent and long-term arrivals into New Zealand, accounting for 36 per cent of all migrant arrivals, she said.