The real estate agent sacked from Barfoot & Thompson says he has never spoken to anyone from the Labour Party and doesn't know how they got information.
Grant Hargrave confirmed today he was the agent who had been fired over information used by the Labour Party to drive a debate about people from China buying property in Auckland.
Mr Hargrave said he did not want to be interviewed on this issue. "I very much would rather not talk about it, I'm sorry."
But he did say that he had no idea how Labour had obtained the information he was sacked for passing on.
"I don't know them. I don't know the Labour people. I honestly just don't know [how the party got it]."
Mr Hargrave's business profile as a commercial real estate agent was absent from the Barfoot & Thompson website this morning.
It had previously praised him for have a "wealth of experience in selling commercial and industrial property" over 25 years, mainly in Auckland.
"Grant has been instrumental in the selling of some of Auckland's largest commercial and industrial buildings.
"He uses 'best practice' and transparent real estate procedures and also appreciates the need for a duty of care to achieve maximum price through the auction and tender methods of sale."
The information used by Labour to crunch numbers on foreign owners - first reported in the Weekend Herald - was said to have originated with a real estate company.
However, it has since emerged that it passed through intermediaries before getting to Labour.
Labour leader Andrew Little said he had no contact or involvement with the source of the information.
Labour's housing spokesman Phil Twyford would not discuss the source, claiming the same confidentiality claimed by journalists. "I can't in good conscience say anything about my sources or any of my contacts with the source and I intend to protect that confidence as you would as a journalist," he said.
Labour stands by the data
He believed the data Labour had used was genuine, even though its connection to the original source had grown a number of steps. Asked if Labour could prove its data had not been tampered with after Mr Hargrave sent it to another party, he said: "We did various things to verify it."
This morning he said that Auckland owed the leaker a "debt of gratitude".
"I absolutely stand by releasing that data," he said. "New Zealand is being sold off under our feet."
He said "offshore speculators" were running rampant in Auckland's real estate market.
Housing minister Nick Smith said the vagueness of the source of the material used by Labour's further undermined its data on foreign ownership. "Labour's whole handling of this matter has been a debacle," he said.
Labour had made political plays in recent years over the integrity of government databases, such as that at ACC, he said.
"Their approach on this issue seem to be one of integrity of databases only being important when it doesn't undermine their political purposes. Data from one real estate agency obtained unlawfully through God knows how many hands based on surnames is unreliable."
Treasury report released
It focused on migration as one of the levers which could reduce the heat in the housing market, saying a drop in the number of people coming to New Zealand would reduce prices. The greatest number of migrants came from India, China and the UK.
Officials said immigration had increased in the same years "local residents" were buying more houses.
Officials also found past increases in prices created expectations of future increases.
'Party political animal'
University of Canterbury journalism lecturer Tara Ross said politicians did not have the same liberties in relation to confidentiality as journalists.
She said journalists answered to their audiences while politicians were vying for government. "There are plenty of occasions where material comes through an electorate MP in the first instance. It's an important relationship.
"But it's a difficult relationship on the basis they are a party political animal."
Auckland university's Professor Thomas Lumley - who has blogged about Labour's analysis at statschat.org.nz - said the steps between the source of the information and the analysis raised questions about the data used.
"If there is a chain of people, you have to wonder if the numbers Labour analysed are the same numbers [that were] leaked. There's no evidence its different but you can't tell it's the same."
Last night, Barfoot & Thompson's managing director, Peter Thompson, and chief executive, Wendy Alexander, announced they had sacked a staff member, saying: "The action was taken after careful consideration of all the facts and meeting personally with the member of staff involved."
Mr Thompson had refused to release personal details about the individual or say how the data was passed on, but confirmed it was leaked over a period of months.
"We can also offer no insights into the motivation of the staff member concerned."
Mr Thompson said that while the data was passed to media and political figures, it was not given directly to the Labour Party.
Asked whether the level of debate and depth of feeling the leaked information had caused justified the means, Mr Thompson said: "We don't want to get into that debate."
The data released by the Labour Party, and published in the Herald, showed 39.5 per cent of Auckland house sales between February and April were to people with Chinese surnames, despite people of Chinese ethnicity making up just nine per cent of the population.
Labour says the data suggests non-resident Chinese buyers are aggressively targeting the Auckland housing market, driving up house prices and pricing first-home buyers out of the market.
They have called for restrictions on foreign buyers, but the party has been accused of racism by the Chinese community.
What the data shows
The leaked data
• Labour received leaked figures covering 3,922 Auckland property sales by one real estate firm from February to April this year. It carried out its own analysis on the figures, using surnames combined with other data.
• Labour used a statistical technique called Bayesian analysis to estimate ethnicity from surnames. This combines a number of data sets, including Census meshblock data and the electoral rolls database, to estimate the probability of whether a name is European, Maori, Chinese, etc.
• The analysis cannot prove statistically whether a buyer is a foreigner or local. Labour's view that most buyers must be from overseas is based on the fact that ethnic Chinese make up only nine per cent of the population but 39.5 per cent of the house buyers. However, the Census figures are from a large base of 1.4 million people, whereas the house buyers' data is from less than 4000 sales.
• The data comes from one agency and does not show sales by other agencies. It does however contain 45 per cent of the sales in that period in Auckland.
• The Weekend Herald has seen the leaked sales figures data and reviewed Labour's methodology. The party updated its figures based on our feedback. We were not able to redo the analysis independently, as it relied on data sets such as the electoral rolls database, which is only available to political parties.