At least 20 people were injured, two of which were in critical condition, after tornadoes and powerful storms slashed through Victoria's northeast on Thursday night, which also toppled trees and ripped off roofs and shattered glasses from windows of dozens of homes and businesses.

According to the SES, the powerful storms hit the Murray River towns of Yarrawonga, Bundalong and Rutherglen at 8pm (AEDT).

"It looked like a war zone," an unidentified resident from Tatong, south of Benalla, was quoted by the ABC.

"It is just devastating, there are trees everywhere all over the fences, 15 foot trees have been cut-off at the ground."

Two of the critically injured, both aged 50, were flown to the Royal Melbourne Hospital Alfred Hospital. The first sustained head, pelvic and abdominal injuries, while the second had serious head injuries.

Another will be taken to Melbourne on Friday morning for spinal injuries when a tree fell on the owner's vehicle while inside it.

"The sorts of injuries we've seen have ranged from serious head injuries, spinal injuries and fractures to cuts and bruising, so far paramedics have treated 20 people and taken them to hospital," Paul Bentley, Ambulance Victoria spokesman, said.

He added they expect more people to come forward with injuries once things have subsided.

The roof of the post office in the town of Barooga was blown off, according to the Border-Mail.

Max Steward, Barooga Post Office manager, said the mini tornado lasted only five minutes, but managed to rip off the establishment's back verandah, sending it 30 metres into the street.

"It just was like a mini tornado," he said.

"A couple of houses down the road ... were literally blown apart by the force of the wind."

Damages that resulted afterward from the tornado hit briefly forced the closure of the Hume Freeway near Benalla.

The SES said it received more than 150 calls for help on Thursday night from the region.

"I'm hearing constant stories... At Bundalong a great big red gum tree was stripped bear, trunks broke off, a number of houses damages some quite severely, powerlines down and I understand they will be down till midday," Brian Keenan, Moira Shire Mayor, said.

"This is certainly a very unusual event to occur in Victoria," Peter Swan from Ambulance Victoria said. "Certainly some of the fiercest weather I've seen, and some of the more experienced hands have echoed that view."

The full extent of damage would be known later on Friday.