Labour is disputing the Government's numbers on properties sold to foreign buyers, saying they could be majorly understated.
New figures show the number of properties being sold to foreign buyers in Auckland almost doubled in the second quarter of 2016.
From April 1 to June 30, only 3 percent of buyers indicated an overseas tax residency - the same as January through March, according to Land Information New Zealand (LINZ) data released today.
But in Auckland, that figure's 5 percent - up from 4 percent in the previous three months. Between January and March, 474 properties went to foreign buyers. Between April and June, that rose to 900.
Three percent of sellers nationwide also had overseas tax residency, up from 2 percent. Sixty percent of transfers were between locals, up from 50 percent.
But more than a third of buyers - 37 percent - weren't required under the rules to provide their tax information, and LINZ is adamant it's not a register of foreign ownership.
"For properties where there's a home on the land, 1695 transfers (3 percent) didn't involve buyers who were New Zealand citizens or residents, 41,694 (82 percent) indicated that they were citizens or residents, and 7521 (15 percent) involved trust companies or businesses," says LINZ deputy chief executive Russell Turner.
There were 57,678 property transfers in total over the three months. Only 1749 of them involved foreign buyers and 1560 foreign sellers, both including trusts and businesses.
Labour leader Andrew Little says the Government is continuing to mislead people about the impact of foreign speculators by using "selective data".
He says it could be underestimating the effect of foreign buyers by 75 percent.
"National has removed the ability for corporations and trusts to be identified as foreign so has skewed the data from the start. They have also counted foreign students and temporary workers who don't intend to stay in the country or live in the home they've bought as New Zealanders."
Mr Little says both those groups would be exempt from buying properties under the party's ban on non-resident foreign buyers.
He says the Government's data includes properties bought via a corporation or trust as a domestic sale - something which is "demonstrably misleading".