Wild weather and wind is expected to persist for days in several states as authorities warn Victorians and Tasmanians to batten down and prepare for power outages.
Victoria's State Emergency Service urges the community to be alert on the roads and avoid driving if possible in heavily treed areas for the next 36 hours.
"Victorians need to act and prepare now for what might be the strongest weather system we've seen this winter crossing our state," chief operations officer Tim Wiebusch told reporters on Tuesday.
The Bureau of Meteorology has issued severe weather warnings for damaging winds across southwest WA and parts of SA, NSW, Victoria and Tasmania.
Flooding is also possible in Tasmania's major rivers and parts of the northwest coast, while dangerous coastal conditions on Victoria's southwest and east coasts could cause erosion and abnormally high tides for parts of Port Phillip Bay and the Gippsland coast.
Wind gusts of above 90km/h have already been recorded at Aireys Inlet, Kilmore Gap and Mount Hotham in Victoria's alpine region.
"Damaging winds above 90km/h have the potential to bring down trees and power lines and create dangerous road and transport conditions, while destructive winds above 125km/h can cause significant damage," bureau meteorologist Jonathan How said.
Winds are expected to increase into the night and could persist until a brief reprieve on Thursday evening, with a less-intense system bringing more blustery conditions on Friday.
"Even as the cold front moves through on Wednesday, we will continue to see very strong winds, particularly across southern parts of Victoria," Mr How said.
Up to 200mm of rainfall is expected in the next seven days across Tasmania, where State Emergency Service acting assistant director Cheryl Ames urged the community to be vigilant.
"The combination of high soil moisture and damaging to destructive wind speeds increases the chances of trees being brought down," Ms Ames said.
Community members are encouraged to secure loose items such as outdoor furniture and trampolines, and to park away from trees.
Meanwhile, Ausnet urged Victorian customers to prepare for potential power outages, and said life-support customers should be ready to activate their emergency plan.
"Have battery-operated torches and radios in a place easy to access," Ausnet media manager Nici de Ryk said.
"Charge your battery packs so they're ready to power your mobile phones (and) keep some cash on hand in case electronic payment systems go down during an outage."
Ausnet has additional field crews on-hand and could call on more resources if needed, and restoration times could be longer than usual depending on network damage.
"We have temporarily stationed generators in Emerald, Cockatoo and Mirboo so they are ready to be connected to provide backup power if the storm impacts the network," Ms de Ryk said.
"They may be relocated to areas of most need as the storm impacts become clearer."
Powercor was also monitoring the weather and had boosted field crew numbers, network operators and customer specialists ahead of the storms.
The warnings come after Sunday night storms left thousands without power until Monday morning.
Emergency service volunteers in Victoria have responded to more than 500 calls for assistance since Sunday with hundreds of trees down across the state.
