NZ First leader Winston Peters says he had the leaked real estate data on Chinese buyers too, but chose not to release it because of the "absence of information".
Labour has been criticised after releasing data leaked from real estate company Barfoot & Thompson, showing that 40 percent of houses sold in Auckland went to people with Chinese surnames.
"The data does not quantify with exactitude what I'm talking about," Mr Peters told TV3's The Nation today.
But he said it was fair to single out Chinese buyers.
"Well, if you are facing stark facts of a preponderance of buying from one country because of unique economic circumstances and governmental circumstances in that country, of course it's fair to say it," he said.
"Anything else is a denial of fact."
Housing Minister Nick Smith told the programme the analysis was not credible and he did not believe "fair-minded" New Zealanders would make a judgment on the basis of people's names.