The warning came as Auckland's property market continues to boom. Real Estate Institute figures for January showed Auckland's median price up 8.1 per cent compared with 2012.
Harcourts chief executive Hayden Duncan said the idea that property prices were at risk of plummeting was almost scare-mongering.
"In order for that to happen, you need to have an oversupply of a product. There is no chance that we have an oversupply of homes or housing or accommodation in the major cities in New Zealand.
"I think the reality is, their comments are probably irresponsible and possibly uneducated in relation to this particular part of the world.
"I don't think there's any chance that it's going to plummet or decline any time soon."
But financial commentator Bernard Hickey said that while Auckland's property prices were "on another planet" because of lack of supply and continuing demand, they were not bulletproof.
"The economy would have to significantly slow down, you would have to see a sharp drop in the dollar, and an increase in interest rates. And at the moment there's no obvious suggestion that that's close by."