The exodus of New Zealanders across the Tasman is out of the control of both governments and has more to do with economic, social and environmental factors, a leading Australian population academic says.
In the year to July a net total of 32,600 people moved to Australia, up from 16,500 the year before and higher than a 10-year average of 21,000.
Professor Peter McDonald, who heads the Australian Demographic and Social Research Institute at the Australian National University, said the flow of New Zealanders to Australia was largely determined by relative economic conditions, including wages, in the two countries.
The trend was "out of the control of either government'' but its impact on the New Zealand labour force was so large that the Government must compensate with one of the world's largest immigration programmes per capita.
Professor McDonald said both countries had similar immigration programmes but New Zealand's was more advanced in what he said was called "the new flexible approach to migration''.
Under that approach, migrants made an initial temporary move, employers became involved, and applications for permanent residency were made once in the country.
Professor McDonald's comments come ahead of his appearance as guest speaker at a University of Waikato seminar, hosted by the National Institute of Demographic and Economic Analysis.
His speech on Thursday will focus on recent immigration debates in Australia and a new government report on the issue.