National rents in Australia fell by 0.1% in September, bringing the median weekly rental value to $436, according to CoreLogic. Rents have remained on a slump consistently for the last three months as the market fails to soak the supply glut.

Also read: Housing Affordability Up, Rental Affordability Down

The substantial increase in rental supply was driven by the surge in investment and residential construction activity through the previous housing boom, CoreLogic head of research Tim Lawless said.

"Additionally, as first-home buyer numbers have surged, this has likely contributed to a reduction in demand as renters convert to buyers," he said.

Rental rates across the combined capital cities came in 0.2% lower over the month, with a median weekly rent of $464. This value remains considerably higher than the combined regional markets, where the median rent currently sits at $381. Rents across regional areas have risen by 0.1% over the same month.

Read more: How Did The Rental Market Fare In August?

Of the capital cities, only Adelaide posted a monthly rise in rents at 0.1%. Sydney and Canberra registered the most significant declines at 0.3%.

During the month, homes in Hobart became more expensive to rent than those in Melbourne. The state capital recorded the third-highest median weekly rental value at $464, after Sydney's $571 and Canberra's $538.