21810 – Public Investment Intensity

Public Investment Intensity (21810) measures how much the public sector is investing in each state and territory relative to the size of that state’s economy: public spending on new fixed assets (roads, rail, hospitals, schools, water and energy networks, and Commonwealth facilities) as a share of state final demand. Higher readings mean more public investment relative to the state economy. It publishes eight readings, one per jurisdiction, each read against that jurisdiction’s own history, and it is the first node of State & Territory Conditions (21800).

Public investment builds the transport, utilities and social infrastructure that new housing depends on, and in a construction-heavy period it competes with residential building for labour and materials. The node reads the scale of that effort, not its quality or where within a state it falls.

Primary metric: Node Z-Score by state (Z_21810,s)

Two reference periods. The z compares the share with the state’s 2011–2025 average, the platform’s standard baseline. That period sits on an upswing: within it the share rose with time in six of the eight jurisdictions. The position ranks the share against every quarter since June 1985, 165 quarters, over which the share fell with time in every state, because public investment was a larger share of state economies in the 1980s. A state can therefore read above its recent average and still sit in the middle of its four-decade history.

Tier-1 sovereign statistical release. Four-quarter sums begin in the June quarter 1985. ABS revises the national accounts each quarter, so recent quarters can move. No commercial data provider dependency exists within this node.

Four quarters to June 2026, ordered by reading. Each z is against the state’s own 2011–2025 average; each position ranks the state against its own 165 quarters since June 1985.

Public investment by state, four quarters to June 2026, split by sector. Commonwealth public corporations sit in both of the last two columns, so the shares do not sum to 100%.

The ACT reading is mainly Commonwealth investment in the national capital. In Tasmania and Western Australia most public investment is by public corporations, chiefly energy and water businesses. Elsewhere state and local government accounts for 56–60%.

One chart per state on the same scale, from 2011. Each line is the state’s z against its 2011–2025 average; the shaded band is the middle 80% of the state’s 165 ranked quarters, which reach back to 1985.

The share itself, June 1985 to June 2026, on the same scale for every state (gold line). The dashed slate line is the state’s 2011–2025 average, against which the z is measured; the dot is June 2026. Shares were highest in the mid-1980s and lowest between 1998 and 2013. South Australia’s dip below zero in 2000 records the sale of public assets.

In the four quarters to June 2026, public investment was above its 2011–2025 average relative to the state economy in seven of the eight jurisdictions; the ACT was below (−0.5392σ). South Australia read highest (+1.7925σ, 6.13% of state final demand), its highest since the March quarter 2018, after rising in each of the 13 quarters since its March quarter 2023 low.

Against four decades the picture is more moderate. Only South Australia (82.3), Tasmania (75.0) and Victoria (72.0) sit in the upper part of their own histories; Queensland (39.0) and the ACT (22.6) sit in the lower part. Shares peaked in most states in the mid-1980s, at 12.6% in the Northern Territory and 10.3% in Tasmania, and reached their lows between 1998 and 2013.

Seven of the eight readings have eased over the past year; South Australia’s has risen. New South Wales is at its lowest since the March quarter 2022, the Northern Territory since the December quarter 2022, Western Australia since the March quarter 2023, Queensland since the December quarter 2023 and Tasmania since the June quarter 2024. Tasmania fell from +2.1374σ to +0.8643σ in the June quarter as a large June quarter 2025 outlay ($1,504 million, against about $900 million to $1,000 million in neighbouring quarters) left the four-quarter window.

The other state measures and the state labour reference.