The Reserve Bank's deputy governor has waded into the debate over foreign ownership of property, saying it would be useful to have better data on the housing market.
Grant Spencer said better information would be useful, but it would be up to the Government to collect it.
Mr Spencer said foreign investors appeared to make up less than 10 percent of the housing market, though the information was not robust.
"It would be useful to know more clearly what's happening in the market in terms of the different buyer segments, but it is a serious proposition in terms of how you get hold of that data."
Housing Minister Nick Smith said the sheer cost and effort is not worthwhile considering the small number of overseas buyers.
But the Labour Party said Dr Smith was out of touch, and the central bank deputy governor's comments proved the need for more comprehensive data.
Labour's Phil Twyford said it would not be unreasonable, nor hugely expensive, to simply record a buyer's citizenship and place of residence at the time of purchase.
Mr Twyford said thousands of New Zealand houses were being directly marketed to buyers in China on the basis that there is no capital gains tax nor any restriction on foreign buyers.