Residents and tourists in parts of north-east Victoria have been sent SMS alerts urging them to evacuate as soon as possible ahead of a worsening fire threat.

Key points: Authorities say major bushfires in Victoria's north-east risk merging into one 'giant fire'

Authorities say major bushfires in Victoria's north-east risk merging into one 'giant fire' Residents in Corryong and nearby towns are being escorted to safety in convoys

Residents in Corryong and nearby towns are being escorted to safety in convoys The bushfire risk is spreading to Alpine towns including Omeo, Falls Creek and Bright

Authorities fear the hot and windy conditions could cause major bushfires at Corryong and across the border in New South Wales to "suck each other in" and merge into one giant fire.

A series of fires started in Victoria's Alpine region by lightning strikes could also pose a serious threat to nearby towns including Harrietville, Wandiligong and Bright, while visitors to Falls Creek and Dinner Plain are being advised to leave the area now, with three out-of-control fires posing a looming threat in the area.

Text messages have been sent to people in the Upper Murray, Upper Ovens, Kiewa and Kings valleys, directing recipients to a warning urging them to leave for regional centres like Wodonga or Wangaratta by tomorrow morning at the latest.

Both cities have been identified as being defendable by emergency services.

"These locations [in the Upper Murray, Upper Ovens, Kiewa and Kings valleys] are expected to be impacted by fire, spot fires and ember attacks or the fire will close major roads resulting in communities being isolated," the warning says.

"If you do not leave today you may become isolated and your route to safer locations may be blocked."

A map issued by Emergency Management Victoria showed a large area of north-east Victoria under potential threat.

A large area of north-eastern Victoria could be impacted by bushfires over the next two days. ( Supplied: Emergency Management Victoria )

Deb Abbott, the Deputy Emergency Management Commissioner, said there was a limited opportunity for people to move to safer areas before Friday afternoon.

"We have a small window of opportunity. It's a window of opportunity for people in those areas to leave now, and we want them to leave now.

"These conditions that we're facing on top of what it is that we have in the landscape now means that the fire risk is much greater."

Burnt trees line the road into Corryong in north-eastern Victoria. ( ABC News: Ashlee Charlton )

Ms Abbott said existing fires were proving to be unpredictable in the north-east of the state, including the Murray Valley, and Alpine areas as well as East Gippsland.

"These fires have already caused significant damage. They've caused significant loss, and our community needs to act now," she said.

People in nearby Bright, Porepunkah and Myrtleford have been urged to monitor warnings.

Convoys out of Corryong

More than 500 fire crew and support staff were fighting the fires near Corryong on Thursday afternoon.

Authorities were arranging escorted convoys leaving from the Corryong relief centre, on the Murray Valley Highway towards Tallangatta, at designated times when conditions allow.

Cudgewa resident Joshua Collings lost everything in the bushfire. ( ABC News: Ashlee Charlton )

Just north of Corryong, Cudgewa resident Joshua Collings lost everything in the fire and started a GoFundMe page for the community to help raise money for water and power generators.

Relief centres: Corryong High School

Corryong High School Tallangatta Memorial Hall

Tallangatta Memorial Hall Wangaratta Performing Arts Centre

Wangaratta Performing Arts Centre Wangaratta Showgrounds (for people with animals)

Wangaratta Showgrounds (for people with animals) The Cube, Wodonga

The GoFundMe page had raised more than $50,000 by Thursday afternoon.

"I've heard there are 20 houses lost, lots of our friends' houses, we have lost everything except for our lives because we left when we were told to and when we thought would be right," Mr Collings said.

"It's really bad, it's black, the ground's black, the sky is black and there is just the thickest smoke up there.

"It's a really small town, something like 240 people, one pub that opens for a couple of hours on a Friday night and everyone goes.

"We got generators to the people in Cudgewa within hours of starting the GoFundMe Page," he added.

Cudgewa resident Joshua Collings lost everything in the fire and started a GoFundMe page for the community. ( ABC News: Matthew Doran )

Authorities say water supplies in the Corryong township are at "critical levels" and should only be used for essential needs, however, drinking water in Walwa, Cudgewa and Corryong remains safe to drink.

Communications towers and power supplies to Corryong have been severely affected by the fires, with energy company AusNet Services and Telstra trying to restore services.

Relief centres have been opened at Corryong High School and Tallangatta Memorial Hall.

The Wodonga Showgrounds are also open for people who are completely self-sufficient.

Numerous road blocks, including along the Murray Valley Highway, remain in place.

Extreme weather forecast

In Tallangatta, local incident controller Leith McKenzie said crews were door-knocking as many properties as possible in the region, warning people about the "horror" weather conditions returning tomorrow and Saturday.

"The message to residents is to get out now, or at least to tell people if they're planning on remaining," he said.

He said there was a serious concern that the extreme weather conditions over the next few days could cause the Corryong fire to merge with the East Gippsland blaze to the south, and with fires in the Victorian Alpine region around Bright.

He said crews were also keeping a close eye on the fire burning across the border in New South Wales, which had gone through areas close to Tumbarumba.

Mr McKenzie said if the Corryong and NSW fires burned as predicted, they could "suck each other in" and merge as well.

Animal welfare officers were going through the fire-ravaged Corryong region on Thursday afternoon.

It is understood about 12,000 cattle and 6,000 sheep survived the fire, but many suffered serious burns and will potentially need to be put down.

Mr McKenzie said some of the injuries were due to the animals being forced to stand on hot ground, melting their hooves.

One man reportedly remained unaccounted for. It is understood he left the Corryong relief centre early this morning to check on his property, but as of mid-morning he had not been heard from.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 3 minutes 59 seconds 3 m 59 s The Bureau of Meteorology's Jonathan How explains the weather pattern causing dire fire conditions.

Growing fire risk in Victoria's High County

South-west of Corryong, concerns are mounting in the Alpine areas around Omeo, Dinner Plain and Falls Creek, with three out of control bushfires north-west of Anglers Creek.

The fires are burning in dry forests and increasing in size.

Tourists in the Cobungra, Dinner Plain, Falls Creek, Omeo, Shannonvale and surrounding forests have been advised to leave the area immediately.

Residents have been warned there are multiple fires burning out of control that may impact communities in coming days.

Residents at Dinner Plain have been told to remain vigilant for any change in conditions, and enact their bushfire survival plans.

Community meetings were being held at Omeo and Benambra on Friday afternoon.