A legal challenge to Auckland's Unitary Plan is being considered by a group which opposed widespread housing intensification.
The proposed 30-year vision for Auckland from the Independent Hearings Panel focuses heavily on increasing housing density in the city, with little left in the way of protecting character suburbs.
Under the proposed plan, nearly 60 percent of Auckland will be zoned for higher density housing, with a 22 percent decrease in areas for single housing.
The plan includes provision for more than 400,000 new houses over the next 25 years as Auckland's population increases.
But it removes partial protections for neighbourhoods with houses built before 1944 - so-called character suburbs.
Auckland 2040 believes the Independent Hearings Panel has gone beyond its legal brief.
The group was behind big public meetings in Auckland's eastern suburbs.
Chair Richard Burton says the panel is bound to stay inside the range of density proposed by submitters to the plan, but appeared to have "proposed quite a number of changes that don't appear to have any substantive submission to support them."
Mr Burton said the group was "questioning the legal validity" of that and would need to decide within weeks whether a legal challenge could be mounted.
The Grey Lynn Residents Association said the Unitary Plan could have included intensification without removing heritage protection for large numbers of homes.
Committee member Brandon Wilcox said his group was in favour of intensification, such as apartment buildings along the Great North Road ridge.
But he told Morning Report removing heritage protection for single-dwelling residential zones made no sense. "All it means is that you can pull down a villa and put up another single house."
The plan recommended by the panel reduces by 22 percent the proportion of the city limited to single homes on sections, and nearly doubles the extent of three-storeyed developments compared with the 2013 proposed version of the plan.
Generation Zero has fought in favour of intensification as a solution for Auckland's housing need.
"The council just really needs to get on to passing the plan," said the group's Auckland director, Leroy Beckett.
"This isn't a time for political grandstanding and we really need to get on with starting to fix this housing crisis."
Property Institute chief executive Ashley Church said the intensification proposed in the plan was inevitable.
"It's the kind of thing that we all recognise has to happen - intensification, expanding of boundaries, the increase of the target over the next 30 years."
But some parts of the plan were alarming, he said, with the partial protections that currently existed for neighbourhoods with houses built before 1944 - the so-called character suburbs - removed.
Regulations on the sustainability of new dwellings had also been removed.
"I'm certainly not advocating that we should protect every single one of those dwellings in those suburbs - often there's quite strong cases to allow that demolition to take place - but you need a process for doing that."
"By effectively abdicating those rules in their entirety, you go from having a system that's too far weighted one way, to a system that almost rejects our heritage completely, and in doing that, you kind of throw away the soul of what makes this city what it is."
Heritage expert Alan Matson said there was no going back once Auckland's historic sites were eroded.
"The danger in that is that you lose your areas of historic heritage. That's irreversible, and it seems foolhardy to me."
He said Auckland was a big city, and there was plenty of room to increase density.
"It's a question of where it's put, and it just seems pretty stupid to go put that in the nice places. Go and put it where it fits in."
He said it makes sense that high density houses are built along the transport corridors. And assurances were also needed that quality homes were being built.
Don't ignore business use - Colliers
The research director of an international property company warns there needs to be land left in Auckland for commercial and industrial uses.
Alan McMahon of Colliers International told Nine to Noon the company was seeing the highest demand for commercial and industrial properties in 20 years.
He said there had to be protection for this kind of land so it was not consumed by residental development.
"One of the points made in the panel report is that some of that future urban should be changed, in terms of the zoning, to light industry or heavy industry or other business uses - which we think is pretty positive and helps clarify what uses will be allowed and will help stop any protential encroachment."
Mr McMahon said there would be more construction and infrastructure, which will mean more jobs and will be good for the economy - but there will be more disruption as well.