This country's population had a net gain (the excess of long term arrivals over long term departures) of 4100 people in December, down from its peak of 5200 in October and the lowest monthly net gain since May last year when it was 4000, according to Statistics NZ.

However the high migrant inflows during the earlier months of last year meant the annual net population gain from migration was 50,900 in 2014, the first time it has ever exceeded 50,000 a year.

Over the last 20 years the net gain of migrants has averaged 13,300 a year.

Total migrant arrivals reached a new high of 109,300 last year compared with 94,000 in 2013, a 16% increase.

At the same time, the number of people leaving the country permanently declined 18% to 58,400 last year, compared with 71,500 in 2013.

The biggest growth in migrant arrivals last year came from India, up 4600 compared with 2013, Australia, up 3700, China, up 1300 and the

Philippines, up 1200.

The fall in migrant departures last year was mainly due to fewer New Zealand citizens moving to Australia.

That has dropped steadily over the last two years, from 48,800 in 2012, to 23,700 in 2014.

For the whole of last year, the net loss to Australia was 3800 people, compared with 19,600 in 2013 and 38,800 in 2012.

Around the regions, Auckland's population gain from migration was 23,000 last year, followed by Canterbury (6000), Waikato (1800), Otago (1400), Wellington (1400) and Bay of Plenty (1200).

Statistics NZ said the net gain of migrants in Auckland, Canterbury and Otago was mainly due to more people arriving, while in the Waikato, Wellington and Bay of Plenty it was mainly due to fewer people leaving.