Whenever they are asked - with increasing frequency - why they do not follow Australia's example and ban foreigners from buying existing homes, John Key and Nick Smith, his Building and Housing Minister, have a stock response: it has not worked across the Tasman. Therefore, ipso facto, it would not work on this side of the Ditch.
The Australian law - they say - has not stopped foreign nationals from purchasing "established" houses. Neither has the policy stopped the surge in house prices in the overheated Sydney and Melbourne real estate markets.
"Spectacularly unsuccessful" was the Prime Minister's dismissive verdict at his weekly press conference yesterday when questioned on something which also happens to be New Zealand Labour Party policy.
Key and Smith are technically correct when it comes to existing homes. But they are not really telling the whole story.
Blame for foreigners flouting the law regarding the purchase of such homes - New Zealanders are exempt from its provisions - has been firmly sheeted home to the Australian Treasury and its adjunct, Australia's Foreign Investment Review Board.