Significant rainfall is expected to continue across much of a state that's already been battered by storms and flash flooding.
Melbourne recorded one of its wettest October days in several years after the city received up to 25mm of rain within an hour on Thursday afternoon, with other areas of Victoria also hard hit.
More than 200 calls for help were made to the SES, including six water rescues, after parts of Melbourne were hit by the flash flooding.
The city was plunged into darkness about 3pm as the system moved through, with Melbourne Olympic Park recording 47.8mm of rain since 9am on Thursday.
Bureau of Meteorology senior meteorologist David Crock said the total marked the city's highest daily rainfall total since April 2024.
"(It was) a very wet day for the Melbourne metro area, particularly in the afternoon when that heavy rain moved through," he said on Friday morning.
"That caused a lot of a lot of water all through the suburbs. Some flash flooding in the creeks and a lot of water under bridges."
Rainfall totals of 20-50mm around Ballarat and Melbourne were also recorded on Thursday afternoon, Mr Crock confirmed.
South Australia also recorded significant rainfall, with 20-25mm falling across parts of the Adelaide Hills in the past 24 hours.
Emergency crews were kept busy overnight, with 200 requests for assistance, 71 of those were for building damage, 50 for flooding and 44 for trees downs.
"We have assisted Victoria Police with six water rescues, vehicles getting into trouble due to entering flood water or driving in roads that had water catching due to the rainfall that fell pretty quickly in a short period of time," the state emergency service's duty officer Jessie Schleibs told AAP on Friday.
"It's one of the wettest October days we've had in several years."
The busiest units included Barwon southwest and metro Melbourne areas, although attention will now move northeastern suburbs along with Gippsland.
Rainfall will continue on Friday and Saturday in Victoria, with a flood watch current for catchments across much of central and eastern parts of the state.
"There is much more to come," Mr Crock said.
"We're expecting more rain through Friday and Saturday. Some spots in eastern Victoria could see 100 to 150mm over the next few days."
Conditions are expected to ease on Sunday as the low pressure system moves off offshore. So conditions will ease from the west.
"Melbourne and Sydney and Canberra and Adelaide should see mostly dry conditions by Sunday," Mr Crock said.
