"Our industry needs a long-term, effective working plan for the region and certainty is important for business," the pair said.
Aucklanders have until May 31 to make submissions.
The Property Council, representing commercial property funds and multi-unit residential property owners, managers and investors with real estate worth about $30 billion, has held a series of workshops and meetings with the council which Townsend and Brown said was receptive to some concerns.
The plan is overly prescriptive on sustainability, they say, setting "unattainable benchmarks" for all new commercial buildings.
"We are talking to the Auckland Council and the New Zealand Green Building Council about our concerns," they said.
Although this was a laudatory aspiration, they objected to it being mandatory.
The Unitary Plan calls for new buildings of 5000sq m or more to be built to a five-star level to reduce energy and water use, minimise environmental impacts and create healthy, comfortable environments.
Townsend and Brown are concerned about value uplift proposals, where the council proposes imposing a betterment levy - taking money from a landowner who gains financially from rezoning.
That money would then be used to fund infrastructure and support affordable housing development, the plan says.
"At the moment in New Zealand, any increase in land value resulting from the rezoning decision remains with the landowner.
A number of countries provide scope for local councils to obtain part of the land value uplift from landowners," the Unitary Plan says.
Townsend and Brown spoke out against inclusionary zoning where developers would be required to build a portion of affordable houses in any new project in return for non-monetary benefits like planning bonuses or fast-tracked consents.
Unitary Plan obstacles
* Auckland Council elections this year.
* Ratepayer resistance to density and height.
* Market realities: the plan is aspirational.
* Past shoddy developments.
- Source: Property Council of NZ
