Net migration is continuing to run at record highs but there are signs the inflow has reached its peak.
April's net migration firmed to 5520 in April, marginally higher than the 5330 in March and the fourth-smallest increase in the past 12 months.
Westpac chief economist Dominick Stephens said monthly figures had been rising aggressively for years but levelled out at about 6000 from October last year to February this year.
In the past two months they had been significantly lower than 6000.
The turn in migration had two drivers.
After falling to very low levels, the number of New Zealanders departing for Australia had stabilised in recent months.
Secondly, the number of foreigners arriving on student visas had fallen sharply, possibly as a result of the tighter English language requirements that were recently imposed.
"We expect net migration to fall over the years ahead as the improving Australian labour market entices more Kiwis across the Tasman and as the surge of students who arrived in recent years on temporary visas begins to depart the country.''
ASB economist Daniel Snowden said the timing of Easter could be a factor in recent volatility in migration numbers.
The details showed arrivals back above the 10,000 level again after March's dip but departures were at their highest level since June last year.
On an annual basis, 68,111 new migrants was a record high.
Tourism growth was down 1.1% month-on-month in April.
However, March was much higher than recent averages, he said.
Annual growth was still at 11%, underlining the continued strength of the sector, he said.
China's burgeoning middle class was boosting the pool of potential tourists.
An increased number of holidaymakers from the United States and Australia were further contributors to the sector's growth.
The increase in tourist numbers and international students had helped boost the export of services, which was now the strongest-performing sector of the New Zealand economy, Mr Snowden said.
