Bank of New Zealand economist Doug Steel says a surge in immigrants will put pressure on existing housing stock, and potentially push up prices.
Official figures show the number of people moving to New Zealand to live long term has hit its highest level in four years.
The figures show a seasonally adjusted gain of 2,300 immigrants in June, because of more arrivals and fewer New Zealanders going to live in Australia.
That is the highest net gain since May 2009.
Mr Steel said the Australian economy slowing down and more job opportunities created by the Canterbury rebuild are behind the increase.
However, he said the boost in immigrants will put pressure on domestic resources.
"Often in New Zealand inward migration goes more to Auckland and outwards tends to come from rural New Zealand."
Mr Steel said that could put even more intense pressure on the Auckland housing market.
