28/12/2016 11:52 AM AEDT | Updated 28/12/2016 12:12 PM AEDT

Storm Wreaks Havoc On South Australia, Heads For Victoria

Victorian residents are being told to brace for heavy rains after SA copped it.

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A general view of the Brighton Jetty and the coastline near Seacliff on September 29, 2016 in Adelaide, Australia. South Australia was plunged into darkness overnight, as the state suffered a complete blackout, following a severe storm. (Photo by Daniel Kalisz/Getty Images)

More than 100,000 South Australian properties could be left without power for more than a day, after a destructive storm tore through parts of the state.

SA Power Networks say flooding from the storm, which barrelled down on parts of the state with winds of up to 120km/h, are hampering repairs after the storm caused flooding and felled trees in some suburbs.

The low pressure system is now headed to Victoria, where residents are being warned to brace for severe weather,

The Bureau of Meteorology said damaging winds averaging 60 to 70 km/h with gusts of 90 to 125 km/h were expected over the SA's lower South East on Wednesday morning and early afternoon, and may affect areas including Mount Gambier, Naracoorte, Millicent and Lucindale.

"We have hundreds of trees down, a number of houses without power as we speak," SA SES Spokesman Dermont Barry told the ABC.

"Certainly to the north areas of Roxby Downs, the Iron Triangle, the copper coast area, they've seen flooding and infrastructure impacts as well.

"It's certainly been widespread damage caused by this storm. As you would expect with over 100 mil of rain, winds in excess of 125km/h, the impacts have been widespread."

Enfield resident Rocco Rugari told The ABC he was facing a difficult clean-up after his house was flooded the night before.

"[It] flooded my kitchen, my cellar, everything, and it blocked all my drains," he told the national broadcaster.

The storm dumped almost 100mm of rain in some areas and generated winds of up to 120km/h in the Adelaide Hills.

The deep low pressure system currently located off the Lower South East coast is expected to continue to move southeastwards to be west of Tasmania by Wednesday night.

It is not the first time severe weather has left SA residents without power, following September's blackout after a storm.

The Adelaide storm comes as two people remain missing in the Northern Territory following rains and flooding.

The pair were reportedly part of a group of six people, including an infant, travelling from the remote West Australian community of Kiwirrkurra to Kintore, about 180 kilometres away over the NT border, when they became stranded.

Victorian residents are being warned to brace for severe weather, with heavy rain and damaging winds expected to bring flash flooding as the deep low pressure system that brought destructive winds to SA moves across the state.