Intense rain has lashed Melbourne's outer eastern and southeastern suburbs, leading to flash flooding and fallen trees and cutting power to thousands of properties.
Parts of Victoria's Gippsland and La Trobe Valley also copped a drenching as severe thunderstorms hit the state on Friday.
The State Emergency Service had fielded 550 requests for help by 9.30pm with 175 of them for flooding, 156 for building damage and 180 for trees that had come down.
The Bureau of Meteorology says rain has been particularly intense in the outer eastern suburbs of Croydon, Ringwood, Bayswater, Boronia, Ferntree Gully.
In the southeast, Narre Warren, Cranbourne, Beaconsfield and Berwick have been soaked.
Southeastern Cardinia recorded 63mm by 9pm, 42mm of which fell within half an hour, while nearby Officer received 50mm.
Thorpdale in Gippsland received 63mm and She Oaks near Geelong recorded 58mm.
Some small hail was recorded at Glen Iris and near the Melbourne Airport.
The conditions caused havoc for the city's power networks, with AusNet reporting about 12,000 of its customers were without power at about 4pm.
That figure was down to 6000 by 8.30pm, with the company hoping to have power back for all of those customers by midnight.
PowerCor reported more than 9000 customers without power at 7pm, which was down to 2500 by 8.30pm.
Its crews will work through the night to restore power to those who had lost it due to issues such as fallen trees and bark.
Flooding also caused issues on roads, with all southbound lanes on Narre Warren North Road at Princes Highway temporarily closed in the afternoon.
The wet conditions may stick around until about 9am on Saturday in Melbourne but are expected to weaken as they continue moving east.
Nonetheless, Victoria's northeast is forecast to experience severe thunderstorms on Saturday afternoon which may bring very heavy rainfall, large hail and damaging winds.
A Bureau of Meteorology thunderstorm warning remained in place for parts of East Gippsland, the Mallee, Northern Country and North East districts at 9.30pm.
Rain in the northeast could help temper bushfires still burning in the region.
"I think there will be some assistance - it is still hit and miss, so not a widespread rainfall event, but it will help generally," Bureau of Meteorology senior forecaster Michael Efron told AAP.
"That heavy rainfall actually could be a concern though in terms of flash flooding and landslides, just given the lack of education in those areas."
The State Emergency Service has urged people to remain alert, particularly those in fire-affected areas where heavy rain could pose the risk of landslides and debris strewn across roads.
"Flash floods can happen quickly, without warning and it is important to never enter or drive through flood waters, as it can take just 15cm of water to float a car," SES State Agency Commander David Baker said.