An outback Queensland town has recorded its wettest day in 20 years as ex-cyclone Esther drops a steady deluge across much of Australia.

The small town of Thargomindah, about 1000 kilometres west of Brisbane, had 128 millimetres of rain at its airport on Wednesday, topping the 118 millimetres that fell on February 22, 2000.

It is the town’s wettest day on record – but Bureau of Meteorology records for Thargomindah Airport officially started only in 1999. However, in even better news for locals, Wednesday’s rain almost matched the total recorded at the airport in the past two years.

About 30 kilometres from Thargomindah, Anthony Glasson’s Picarilli Station has been cut off by the rain.

Mr Glasson told the ABC his wife could not get home because of the 214 millimetres of rain that had fallen in two days. He hopes the deluge will make grass finally grow again in the drought-declared area.

Other south-west Queensland towns also benefited from this week’s welcome downpours, with Birdsville getting 125 millimetres on Tuesday and Wednesday.

Birdsville residents might have been less overjoyed to also record their coldest March day on record on Wednesday. BOM forecaster Felim Hanniffy said the tiny town’s day-time temperature reached only 21.6 degrees.

The downpours – which came after the remnants of the cyclone met a low-pressure system in South Australia – weren’t confined to rural areas. A steady deluge dumped a month’s worth of rain in Melbourne early on Thursday.

Roads and rail lines were flooded after 50 millimetres fell in the Victorian capital. There was more to come too, with the weather bureau heavy rain and possible flooding of some rivers in central and eastern Victoria later in the day.

The weather was heading for Sydney on Thursday afternoon. The harbour city had a near-100 per cent forecast of five-10 millimetres of rain, with falls continuing into Friday.

“The focus of rainfall has now shifted away from the south-west of Queensland, it is now over the southern interior,” meteorologist Shane Kennedy said.

Thunderstorms and hail were possible for the Warrego, Maranoa and Darling Downs on Thursday.

-with AAP