Sociologist Paul Spoonley says New Zealand is relying on immigration to prop up the population and save the economy.
Professor Spoonley, from Massey University's college of humanities and social sciences, says New Zealand's population is ageing prematurely due to the falling birthrate and young workers leaving for overseas.
He says the 85,000 migrants arriving each year are needed to plug the gaps in terms of skilled young workers.
However, Professor Spoonley, who will be speaking at an international immigration conference at Massey's Albany campus this week, says the country can't continue to lose 54,000 people each year.
He says the Government needs to look at ways to encourage the 1 million New Zealanders living overseas to return.
