Australia's home value index fell 1.1% in September, marking its sixth consecutive monthly decline, with dwelling values now 5.2% below their March record high as every capital city except Darwin recorded a fall, Cotality said in a Thursday report.

Brisbane recorded the steepest monthly decline among the capital cities in September, falling 1.5%, followed by Sydney at 1.4% and Melbourne at 0.7%.

Almost every capital city suburb recorded a decline in value over the three months to the end of September, with 97% experiencing falls, highlighting the broad-based nature of the current housing downturn, said Tim Lawless, Cotality's research director.

The downturn reflects affordability pressures, higher interest rates, rising living costs, and weaker consumer sentiment, which have collectively reduced purchasing power and dampened buyer demand, per the report.

On an annual basis, the housing market remained mixed, with national values flat as Perth and Darwin rose by about 10% and 12%, respectively, while Sydney and Melbourne fell by 7% and 6.2%.

Housing activity has weakened sharply, with sales down over 19% year over year, inventory up more than 23%, and the median time to sell rising to 39 days from 23, pointing to softer demand and accumulating supply.