Tens of thousands of Victorians are facing the prospect of a third night without power after destructive storms wreaked havoc on the energy grid.

Premier Jacinta Allan confirmed about 70,000 homes and businesses remain disconnected from the electricity network on Thursday afternoon, down from 530,000 at its peak.

“There’s obviously still a way to go,” she told reporters at Dadswells Bridge.

Most of those homes and businesses are serviced by AusNet, with the power provider pushing to get another 25,000 back online over the course of the day.

About 400 AusNet crews were working on Thursday to clear debris and repair powerlines to reconnect properties following Tuesday’s catastrophic wind event.

But it could more than a week to restore electricity to some properties, the Australian Energy Market Operator has warned.

Ms Allan said the speed of transmission network repairs was being hampered by safety concerns and closed roads from fallen trees.

“As the numbers get smaller, the task will get harder because we’ve got to go into difficult terrain.

“It’s got to be done safely. In many of these instances, you’ve got to make sure that the power lines that are down aren’t still live.”

Emergency Recovery Victoria is considering options for communities which may be left without power into the weekend, she added.

“I appreciate that communities without power are feeling incredibly frustrated,” Ms Allan said.

The main blackout-hit areas are the Yarra Ranges, South Gippsland and Bass Coast.

“We are hoping to have … the vast majority (of customers) back on by Saturday,” AusNet’s Steven Neave told Nine’s Today show on Thursday.

Despite AusNet owning and managing Victoria’s 6000km electricity transmission system, Opposition Leader John Pesutto accused the state government of ignoring ways to build network resilience in the face of more frequent weather events.

“Victorians have every right to expect their government will make sure distribution companies and the generators … are investing in the infrastructure that’s required,” he said.

The storm led to one of the largest power outages in Victorian history.

Victoria’s State Emergency Service has received some 4250 calls for assistance since Tuesday, with roughly 3300 for downed trees and close to 600 for building damage.

About a quarter of those requests were for incidents in Gippsland, with 53 calls for help in Mirboo North alone.

A dairy farmer in nearby Darlimurla North was killed when he was struck by debris while herding cows on a quad bike on Tuesday evening.

A relief point has been set up at the Mirboo North and District Community Foundation, to provide information, generators for electricity and satellite internet because the town is completely cut-off by the storm damage.

About 750 callout requests were still active statewide on Thursday morning.

Five regional hospitals could remain on generator power for days as authorities rush to prioritise fuel and restore energy to those sites.

Almost 500 phone towers and 450 NBN sites were down on Wednesday, leaving a quarter of a million customers without internet access.

Collapsed transmission lines also caused the Loy Yang A coal-fired power station in the Latrobe Valley to shut down, but authorities insist the widespread outages were caused by local transmission damage.