Twelve months after the legislation for Special Housing Areas was passed, "that's a failure in anyone's book", Labour's housing spokesman Phil Twyford said.
"The Government has had six years in office, surely they have to recognise that whatever they're doing is not working."
Mr Key said his Government's policies would take time to work.
"I wouldn't be surprised if the discussion three years from now is about how many houses are available. There's going to be a hell of a lot of houses built over the course of the next three or four years, there's a lot of land released. If you look at those Special Housing Areas they will account for tens of thousands of new dwellings."
Housing Minister Nick Smith defended the Government's strategy but acknowledged "we have no reliable data on the number of houses that are completed in Special Housing Areas or anywhere".
However, he said there had been 294 building consents granted in Special Housing Areas so far.
Dr Smith said a fall in house price inflation in Auckland over the last year was proof the Government's strategy was working, as was an increase in building activity across the city.
The Auckland City rating valuation data was "simply a reflection of what we had already known. It is encouragement for us to push the accelerator as hard as we can on new housing development and growing supply."