Analysis from ASB has found that Statistics New Zealand's estimate that non-citizens accounted for only 3 per cent of house purchases is well short.
Economists from the bank say the figure more likely sits between 11 and 21 per cent.
Examining transfers or purchases of New Zealand property, Mark Smith and Nick Tuffley analysed the information and reached different conclusions to those released by Statistics NZ.
"The estimates suggest that non-resident purchases made up around 3 per cent of nationwide house purchases over the March 2018 year. This was in a similar ballpark to previously published figures. However, anywhere from 11 per cent to 21 per cent of reported purchases over that period involved a non-NZ citizen, with the proportion considerably higher for some areas, particularly Auckland and Queenstown," they wrote in their latest Economic Note.
Kim Mundy, a fellow ASB economist, said the assumption was that the true figure was at the lower end of the 11 per cent to 21 per cent range "but there's no way to know. We are assuming it is nearer 11 per cent," she said.