The central bank introduced Auckland-specific lending restrictions covering loan-to-value ratios in November last year while the government's more stringent enforcement of taxing speculators' capital gains began in October, moves aimed at countering the impact of record inbound migration and a supply shortage of housing in the city that's driven up prices.
The Auckland market has shown signs that it is heating up again, based on the latest Real Estate Institute data, which showed the median house price in the city reached $820,00 in March, up 14 percent from a year earlier and the first time it had broken above $800,000.
There's an awful lot of Chinese people moving to Auckland - if you allow them to come to this country, it's fair enough they can buy a home here
As a measure to broaden the tax base, a land tax had some merits, the working group's 2010 paper said. It would be an efficient tax in not imposing distortions of economic behaviour, provided it was applied at a single rate, and would generate a large amount of revenue off a low rate, given the nation's $450 billion to $480 billion of property assets at the time.
Inland Revenue could also access existing land and property value data used by local authorities to levy rates.
But such a tax would also be expected to cause "an initial fall in the value of land", could push indebted investors into negative net equity, and could result in more than one outcome in terms of rental properties, the report said. Fallout from the Auckland market was increasingly driving up demand in other regions, the data showed.
"The one area which we as a group were uncertain on as a base-broadening measure was a capital gains tax or land tax," Buckle said. "There are good reasons to be cautious."
Andrew King, executive director of the New Zealand Property Investors Federation, said he agreed with Buckle that more concrete information was needed on the influence of foreign buyers.
"There's a lot of anecdotal evidence and people in the media saying that foreign buyers are a problem in pushing up house prices," King said. "But the housing market is very complicated and it's so important you don't make decisions on what you think is happening."
"Of course if there's money being laundered and things like that happening then we need to deal with it" but more broadly the government needed to take care it didn't attempt a policy response to temporary factors in the market. For example, he said, commentators point to record net migration, of which Kiwis returning home was a part, but that situation in itself could turn very quickly.
There were also race-based assumptions being made, such as property auctions in Auckland being dominated by Chinese investors, when such people could be New Zealand citizens.
"There's an awful lot of Chinese people moving to Auckland —if you allow them to come to this country, it's fair enough they can buy a home here," King said.
Investors as a group also drove demand for rental properties, where New Zealand faced "a real shortage" and it was important any tax targeted at foreigners didn't have the effect of choking the supply of such properties, he said.
Some market analysts tended to liken the property market to the stock market, driven by speculative investors, but housing was much less volatile as an asset class, he said.