Thousands of Victorians will likely have to wait another three weeks to have their power reconnected under revised estimates to fix damage caused by last week’s wild storms.

AusNet, the energy provider to the state’s east and north-east, confirmed initial repair estimates had been wrong for the Dandenong Ranges.

With about 9000 properties and businesses across the state’s east still without power, the energy company said the worst-affected Dandenongs areas should prepare to be off the grid until July 10.

“We are deeply sorry. We now understand the extent of the damage and scale of the recovery and repair ahead,” AusNet said in a statement on Wednesday night.

“This will affect 3000 customers in Ferny Creek, Kalorama, Mount Dandenong, Olinda, Sassafras, Sherbrooke, The Basin, Tremont and Upwey.

“As we progress through repairs, the power will gradually come back on across the region.”

Customers in the worst affected areas of The Dandenongs should prepare to be without power for the next 3 weeks. The initial estimates provided to customers were wrong. We are deeply sorry. We now understand the extent of the damage and scale of the recovery and repair ahead. 1/3

— AusNet Services (@AusNetServices) June 16, 2021

It comes as nearby residents of three storm-hit Yarra Ranges suburbs have been told not to drink tap water until further notice.

The Department of Health issued an urgent warning on Wednesday morning to people who live, work or are in Kallista, Sherbrooke or The Patch not to drink tap water, even if it is boiled, due to contamination.

It is expected the warning will stay in place for at least three days.

“This advice has been issued following an equipment failure at Yarra Valley Water drinking water tank due to recent severe weather,” the warning reads.

“This may result in potentially unsafe water entering the drinking water system and customer taps.”

Emergency water supplies avail 24/7 to customers in #ThePatch #Kallista & #Sherbrooke who are impacted by current Do Not Drink Water Advisory. Locations:The Patch Hall, 5 The Patch Rd,The Patch & The Kallista Public Hall, 6 Tom Roberts Rd,Kallista. 👉 https://t.co/zh8Bs7oRYU 1/2 pic.twitter.com/C7uwrSv4Yr

— Yarra Valley Water (@YVWater) June 16, 2021

The department said special care should be taken to not ingest the water when bathing or showering.

Emergency drinking water will be available at the Patch Hall and Kallista Public Hall, though people will need to bring their own bottles, pots and kettles to fill up.

Two people died in the dangerous storms last week, with minor flood warnings still current for the Latrobe, Thomson and Yarra rivers.

But forecast rain on Friday in the flood-affected Gippsland region is not expected to dramatically affect local river levels.

East Gippsland will have 25 to 40mm, which could lead to minor flooding in the Snowy River, and 5 to 15mm is expected to fall in the west.

“It’s probably not enough to result in significant impacts,” said Christopher Arvier from the Bureau of Meteorology.

Wind strength is also not expected to reach last week’s destructive levels.

The bureau also reported much-needed rain in the north-west and west of Victoria after a dry autumn, with more forecast in the Wimmera.