Zoning restrictions add tens of thousands of dollars to the price of every new home in Australia. Here is what the research says, what reform looks like, and why builders should be paying attention.

There is a tax most Australians have never heard of. It does not appear on a settlement statement. There is no line item for it in a building contract. But it is embedded in the price of almost every home sold in this country, and for some cities it accounts for nearly half the purchase price.

Economists call it the zoning tax.

It is the premium buyers pay for the legal right to put a dwelling on a piece of land. That right is controlled by planning systems, and where those systems are restrictive, the price of that permission inflates accordingly.

New research from the Centre for Independent Studies, drawing on work by economist Peter Tulip, puts a number on it. In Sydney, the zoning tax accounts for 42 per cent of the average home price. In Melbourne, 41 per cent. Brisbane, 29 per cent. Perth, 35 per cent.

These are not rounding errors. They represent tens of thousands of dollars added to the cost of housing not by materials, not by labour, not by site conditions, but by the planning system itself.

For builders who operate inside that system every day, this matters.

What the Zoning Tax Actually Measures

The concept is straightforward. Take the sale price of a finished dwelling. Subtract what it costs to build, including a normal developer profit margin. What remains is the zoning tax, the value attributable purely to planning permission.

When land is rezoned for residential development, its value typically increases immediately. The physical characteristics of the site have not changed. Its location has not changed. But the legal permission to build on it now exists, and that permission holds significant monetary value in a constrained market.

As economist Peter Tulip argues in his paper Housing Affordability and Supply Restrictions, this dynamic is the central driver of Australia’s housing crisis, not demand, not immigration, not interest rates in isolation, but a planning framework that prevents supply from responding to demand.

The logic flows simply. When more people want homes than the system allows to be built, prices rise. If the system then further restricts where and how densely housing can be built, those prices rise further. The gap between what a home costs to build and what a buyer pays for it grows, and the difference sits in the planning system.

“Australia’s housing affordability crisis is primarily the result of planning and land-use regulations that restrict the supply of new housing and make it more expensive.” Peter Tulip, Centre for Independent Studies

The Policies Driving the Problem

Tulip’s research identifies several specific regulatory mechanisms that constrain supply. Exclusionary zoning, particularly single-family-only zones, is among the most significant. In large parts of Australian cities, it is legally impossible to build anything other than a detached house on a residential block. Density, by law, cannot happen there.

Height limits, minimum lot sizes, parking requirements and use restrictions compound the effect. Each rule, individually, may seem reasonable. Collectively, they function as a constraint on supply that drives up the cost of housing for everyone.

Urban growth boundaries add another layer. When a city cannot expand outward and planning rules prevent it from building upward in established suburbs, the available land for housing development shrinks. Prices respond accordingly.

Then there are approval timelines. A project that might be commercially viable at today’s costs can become unviable after 12 months of delays, with interest accumulating on holding costs, materials repricing and labour availability shifting. The process itself becomes a financial risk.

For developers and builders operating in this environment, this is not news. But the research gives precise weight to what the industry has understood empirically for years.

Where Housing Should Actually Be Built

A separate paper by Tulip, Where Should We Build New Housing, raises a related but distinct problem. It is not just that Australia is not building enough housing. It is that the housing being built is largely in the wrong places.

Using Sydney as a case study, the paper finds that new housing construction is heavily concentrated in outer suburbs, while inner and eastern areas with the highest demand and most significant housing shortages continue to accommodate very little new supply.

High house prices relative to construction costs in these areas are a signal. They indicate that demand substantially exceeds supply, that people are paying a premium to live in locations the planning system effectively restricts.

Tulip proposes that state governments set evidence-based housing targets for local councils, targets calibrated not just to population growth but to affordability outcomes. Councils in high-demand, well-located areas should be required to accommodate significantly more development, particularly medium and higher density housing.

The argument is that housing should be built where people most want to live, as demonstrated by what they are willing to pay. Where prices are highest relative to construction costs, the planning constraint is doing the most damage.

High house prices relative to construction costs in established areas are a signal. They indicate that demand substantially exceeds supply, and that planning controls are preventing the market from responding.

What Auckland Did, and What It Tells Us

Australia has a reasonably close international comparison in New Zealand, and specifically Auckland, where the government undertook significant zoning reform over recent years.

At a Centre for Independent Studies forum, NSW Premier Chris Minns pointed to Auckland’s experience as a model that shaped the NSW government’s approach to housing reform. Following Auckland’s zoning changes, which allowed substantially more infill housing across the city, infill construction roughly doubled and rents fell by up to 35 per cent in affected areas. Younger people began returning to the city.

New Zealand Housing Minister Chris Bishop described the broader national reform effort, arguing that housing location should follow where people want to live and are willing to pay, not where planning restrictions happen to permit development.

The Auckland example is significant because it is proximate, comparable and has produced measurable outcomes. It demonstrates that zoning reform at scale can shift market behaviour and improve affordability, even in cities where supply has been constrained for decades.

The results did not happen instantly. But the trajectory changed because the policy changed.

The Demand-Side Policy Problem

One of the more pointed arguments in Tulip’s research concerns demand-side policies, the first home buyer grants, stamp duty concessions and deposit schemes that governments routinely reach for when housing affordability becomes a political issue.

His position is direct. When supply remains constrained, subsidies to buyers do not improve affordability. They raise prices. The subsidy goes to the seller, not the buyer, because the market absorbs it. The result is that public money is spent without solving the underlying problem and in some cases actively worsening it.

This has direct implications for how the industry engages with housing policy debates. Builders understand the problem at street level. They see what gets approved, what gets delayed, what gets rejected. They understand the gap between what a project needs to be viable and what the planning system allows.

That operational knowledge has value in the policy conversation, but only if it is connected to the structural argument about supply constraints rather than channelled exclusively into discussions about grants and incentives.

What This Means for Builders

For builders, the practical implications of this research sit at several levels.

The most immediate is understanding why land costs what it does. When a site is priced significantly above what the construction costs and a reasonable margin would justify, the zoning tax is part of the explanation. That gap does not represent market irrationality. It represents the price of planning permission, and in constrained markets it can be substantial.

The second implication concerns project viability. Delays in the approval process are not just inconvenient. They carry direct financial costs through holding charges, repricing risk and the opportunity cost of capital tied up while a project waits. Recognising this as a systemic feature of the planning environment rather than a project-specific problem changes how builders should approach financial modelling and contract terms.

The third is workforce and capacity planning. If planning reform does take hold at scale, whether through state-based zoning changes, housing target enforcement or density uplifts in established suburbs, the pipeline of work available to builders will change in character, not just volume. Medium density infill in established suburbs requires different skills, different supplier relationships and different site logistics than greenfield detached housing. Builders who understand what reform looks like in practice are better positioned to respond to it.

Finally, there is the policy conversation itself. Builder associations, suppliers and industry bodies have long argued for planning system reform. The research gives that argument a precise, quantified foundation. The zoning tax is not a concept. In Sydney, it is, on average, 42 per cent of the purchase price of a home. That number has weight in a policy debate.

THE GOOD BUILDER TAKE

The research makes something explicit that the industry has felt for a long time. Housing affordability is a supply problem, and the supply problem is a planning problem.

Builders are not the reason homes are unaffordable. In most cases, builders want to build more. The constraint is the system they operate in, and that system adds tens of thousands of dollars to the cost of every home before a single nail is driven.

What is useful about this body of research is that it gives the industry a precise and evidence-based language for a problem it has long understood in practical terms. The zoning tax is real. It is measurable. And the levers that control it are in the hands of state and local governments.

The Auckland comparison is worth watching. Not because Australia should copy another country’s approach wholesale, but because it shows that reform at scale can move the dial on affordability, and that the constraints holding back supply are not permanent features of the landscape. They are policy choices.

For more analysis on housing policy, planning reform and what it means for the construction industry, visit thegoodbuilder.com.au and subscribe to The Good Builder Podcast wherever you listen.

General Information Only: This article is intended for general informational purposes and does not constitute financial, legal, or investment advice. Readers should seek independent professional advice before acting on any information contained herein.

Author: TGB Editorial