Across Australia’s 546 Local Government Areas, the relationship between population growth and building approvals is, on the whole, exactly what a functioning planning system should produce: strong and linear. Over the three financial years to 2024–25, growth and approvals correlate at r = 0.952 nationally — the system broadly responds to demand. The story worth telling isn’t the correlation. It’s the residuals, and they are heavily state-patterned in a way that reframes one of the country’s most-discussed property markets.
The National Picture
Filtering to the 119 LGAs with genuinely significant three-year population growth (above 3,000 persons) and a material approvals base (above 100 dwellings), the average absorption ratio sits at 3.91 persons per approved dwelling. Eighty-five of the 119 run above 2.5 persons per approval; forty-three run above 4.0. These are not fringe outliers — they represent the typical experience of growth-absorbing Australia, not an exception to it.
Full-sample scatter, 529 LGAs with non-zero approvals plotted on a signed-log scale to accommodate the wide range of values.
The Western Australian Outlier
State-level aggregation shows Western Australia absorbing population growth at 4.63 persons per approval — against 2.85 in Victoria and 2.87 in New South Wales. Of the ten tightest-absorption LGAs nationally, eight sit in Western Australia: Vincent (9.85), Victoria Park (9.41), Joondalup (8.77), Mundaring (8.47), Canning (7.79), Kalamunda (7.40), Perth (7.39), and Bayswater (7.29). These are established middle-ring Perth suburbs, not fringe growth corridors — which matters, because it rules out the standard explanation (undersupplied greenfield land release) as the primary driver.
This is the supply-side half of the Perth price cycle, quantified at LGA grain: the market most cited nationally for price growth over this window is also the market where the approved pipeline covers the smallest share of population intake.
What’s Actually Driving It
Splitting each LGA’s population growth into its ABS components — natural increase, net internal migration, net overseas migration — reveals that Western Australia’s absorption gap is not one story but two, cleanly separated by geography within the state.
The inner and middle ring is overseas-migration-led and losing domestic residents. Vincent, Victoria Park, Canning, Perth, Bayswater, Stirling, Belmont and South Perth all show net overseas migration exceeding 88 per cent of total population growth — several exceed 100 per cent, meaning overseas arrivals alone outnumber the LGA’s net population gain, offset by a net outflow of internal migrants (as low as −56 per cent of growth in Canning). These are the same suburbs recording the tightest approval ratios in the state.
The outer growth corridor is domestic-migration-led and comparatively well-supplied. Serpentine-Jarrahdale, Swan, Armadale, Kwinana, Rockingham, Mandurah, Wanneroo and Busselton all show net internal migration as the dominant growth component (30–68 per cent of growth), overseas migration contributing a smaller share, and absorption ratios running 2.5–4.7 — roughly half the burden of the inner-ring cluster.
Read together, this describes a single mechanism: overseas migrants are arriving into inner and middle-ring Perth in numbers the approved pipeline in those specific suburbs is not built to absorb, while domestic movers priced or pushed out of those same suburbs relocate to the outer corridor — where approvals are, comparatively, keeping pace. The Perth absorption gap is not a general undersupply story. It is concentrated in a specific ring of established suburbs receiving an intake their local pipeline was not sized for.
Migration Composition: WA Inner Ring vs Outer Corridor
Two Counter-Narratives Worth Carrying
Two findings complicate any simple undersupply-crisis reading and are worth stating plainly.
Victoria’s scale is not matched by a supply failure. Victoria absorbed the largest absolute population growth of any state over the window — 458,627 persons — at near the best big-state ratio (2.85). The investor-exit narrative that has dominated Victorian property commentary through this period coexists with, rather than contradicts, one of the strongest approval responses in the country.
Tasmania shows the inverse problem. At 0.50 persons per approval, Tasmania is approving roughly two dwellings for every additional resident — a ratio consistent with a market building into a growth slowdown rather than responding to one. This reframes Hobart’s soft market over the period as an absorption inversion, not simply a demand story.
The East-Coast Standout
Outside Western Australia, Randwick is the sharpest single case: population growth of 10,409 against 1,223 approvals (ratio 8.51), with net overseas migration at 176.6 per cent of total growth — overseas arrivals alone almost 1.7 times the net population gain, offset by a substantial net outflow of internal migrants. This is structurally the same pattern as inner Perth: overseas-migration-driven intake into an established LGA approving comparatively little. Sydney LGA (6.74, overseas share 167.7 per cent) and Greater Dandenong (7.15, overseas share 164.9 per cent) show the same signature outside WA, indicating this is not a Perth-specific mechanism but a recurring pattern in specific inner-urban LGAs nationally.
Methodology Note
This analysis covers the 546 LGAs with matched population-components and building-approvals data in the sample analysed only. Population growth is calculated as the sum of natural increase, net internal migration, and net overseas migration across the 2022–23, 2023–24 and 2024–25 financial years. Approvals are summed from monthly dwelling approval data over the matching window, 1 July 2022 to 30 June 2025. The 119-LGA significant-growth sample is filtered to population growth above 3,000 persons and approvals above 100 dwellings to remove small-base volatility. Overseas and internal migration shares are expressed as a percentage of total population growth for the same LGA and window and can individually exceed 100 per cent, or be negative, where components partially offset one another.
Approvals are not completions; demolitions are not netted from approvals; household size varies by LGA, so the 2.5 persons-per-approval reference line is a national benchmark, not a local threshold; population components for 2024–25 are provisional pending revision. This analysis does not assert intent or attribute the migration pattern to any policy cause — it describes a measured compositional relationship only.
