The brother of camper Shannon Lowden, whose body was found along with that of Caleb Forbes on Friday afternoon almost a week after the pair went missing in Victoria's east, has paid emotional tribute to his sister.

Callum Lowden released a statement that said:

"Rest in paradise to my beautiful sister Shannon, the first best friend I ever had. My heart is truly broken right now and we miss you so much already. Every day of my life I will remember the loving and kind person you always were. Forever in all of our hearts, you will always be by my side. I love you."

Police are investigating a car crash they believe led to the deaths of the two young campers.

Key points: Police found the bodies of Caleb Forbes and Shannon Lowden about 11:00am

Police found the bodies of Caleb Forbes and Shannon Lowden about 11:00am Victoria Police said the family of the pair were "understandably devastated" by the deaths

Victoria Police said the family of the pair were "understandably devastated" by the deaths The search had been ramped up during the week to an area of 1,000 square kilometres

Mr Forbes, 22, from Kilsyth, and Ms Lowden, 21, from Lilydale, told family members they were going camping near Thomson Dam and Walhalla in West Gippsland last Friday.

They had not been heard from since Ms Lowden sent a text message to her mother on Saturday.

"Sadly, the pair were found deceased in their car on Trig East track, east of Thomson Dam about 11:00am," police said in a statement on Friday afternoon.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 14 seconds 1 m 14 s Police said the discovery was "very, very difficult" for those who had been searching for the pair.

The pair was due to return home on Saturday but the alarm was raised after Mr Forbes failed to turn up to work on Sunday.

The search efforts were ramped up during the week, with police, SES crews and community volunteers scouring the area using motorbikes, four-wheel drives, helicopters and planes.

Parks Victoria and the Department of Environment, Land, Water and Planning joined the search on Friday.

They were searching an area of 1,000 square kilometres in wet and slippery conditions.

Police had released a photo of the car Mr Forbes and Ms Lowden took on their camping trip. ( Supplied: Victoria Police )

Police investigating cause of accident

Inspector Shane Cashman said the car was found off the track about 5 kilometres east of Thomson Dam, which sits near the Baw Baw National Park.

Aerial news footage appeared to show the campers' car had left the track and crashed into trees.

The footage showed the severely damaged car flipped on its side and resting against a tree.

The crashed car of the missing campers appeared to have rolled down a steep slope next to the track. ( ABC News )

Inspector Cashman said the Trig East track was "a very difficult track to negotiate" and said there would be an investigation into what caused "the accident".

"It's almost a sheer drop to the side and we will put some work into finding out … what has actually occurred to make that car leave the road," Inspector Cashman said.

The two missing campers were found east of Thomson Dam. ( ABC News )

"We've spoken to the family and they are understandably devastated.

"[It is] very, very difficult for everybody concerned, for Victoria Police and SES and all the volunteers.

"There has been a lot of resources that have gone into this, a lot of family, friends and volunteers have turned up here helping out to try and find these two. The support we have had, we can't thank the community enough."

Police said they would prepare a report for the coroner.

Rawson mini-mart shop owner Gurpreet says it is very sad that they found the bodies of the missing campers. ( ABC News )

Rawson mini-mart shop owner Gurpreet (who only provided her first name) said she first found out through Facebook on Friday afternoon that the bodies had been found.

"It's really sad, it's sad for the community and I think it's really hard for the parents to go through this situation.

"I am a mum, I know how it feels to lose your kids and it's really sad.

"I have been there two weeks ago [in the area where they were found] and I won't come back here. It's a narrow track and I think it's only for the four-wheel drives. It's hard to pass through that terrain."