Migration is continuing to drive New Zealand's population closer towards the 5,000,000 milestone.

Latest figures from Stats New Zealand shows the population grew 1.9 per cent last year, with the estimated resident population reaching 4,885,000 in June this year.

Stats NZ Senior demographer Kim Dunstan says because New Zealand is a relatively small country, migration does fluctuate and plays a key role in the results.

"The actual increase continues to chug along at about 30,000 a year, but net migration is currently the main contributor to our population growth. In the last year, it contributed over 65,000."

Dunstan says the statistics say that an average age of the population is also going up.

He says it's only a matter of time before New Zealand starts to see the impacts on society of a growing population.

"A growing population clearly places demand on the infrastructure and services, and a growing older population, they have specific needs in terms of health and other services, so there's certainly indications right across New Zealand society."

LISTEN TO KIM DUNSTAN TALK WITH