"Our data is not a register of foreign ownership. We've collected information for tax purposes as well as some information for housing policy," the spokesman said.
Twyford today raised further questions and challenged the LINZ classification of the data.
"They have 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. Both these groups would be excluded from buying existing properties under Labour's policy to ban non-resident foreign buyers," Twyford said.
"The Land Information data shows 2300 properties were bought by non-residents in the last three months. A further 5700 were bought by people here on temporary visas who did not intend to occupy the property.
"That's 8000 houses sold to foreign buyers in the past three months - 13 per cent of total sales and four times the number the Government is claiming. To make matters worse, National has treated all corporations and trusts as local and so has skewed the data from the start," Twyford said.
The claim that foreign buyers only amount to 3 per cent of the market is not supported by the data, he said.
"Since the initial LINZ foreign data was released all New Zealand's major banks have stopped lending to foreign buyers. They accept what National refuses to - that foreign buyers are a significant presence in housing market.
"National should back Kiwi families and first homebuyers, instead of protecting non-resident foreign buyers, and adopt Labour's policy of banning foreign buyers from buying existing homes," Twyford said.