Police have ended the search for two friends aged in their 70s who went missing during a camping trip in Victoria last month.

Key points: Arson detectives have not been able to determine the cause of a fire that destroyed the campsite of two seniors missing in Victoria

Arson detectives have not been able to determine the cause of a fire that destroyed the campsite of two seniors missing in Victoria Police have broken the news to the families of Carol Clay and Russell Hill that the search for the pair has been called off

Police have broken the news to the families of Carol Clay and Russell Hill that the search for the pair has been called off In a social media post, the CWA remembered Ms Clay, a former president of the organisation, as warm, dedicated, and beloved

Carol Clay, 73 of Pakenham and Drouin man Russell Hill ,74, set off together on the trip along the Dargo River, in Gippsland's Wonnangatta Valley, on March 19.

Mr Hill, an experienced bushman and former logger who knew the area well, last made contact from Wonnangatta Station, four hours south-east of Wangaratta on March 20, using his high-frequency radio.

Police say rain hampered the search and it is now highly unlikely the pair has survived.

It snowed on higher peaks in the area on Sunday.

Inspector Craig Gaffee said he informed relatives today that the search was over.

"Right from the outset I was really confident we'd be able to find both of them," he said.

"The fact that it's got to this stage is really a surprise to me and really disappointing for all searchers involved.

"We are clearly thinking of the families of both at this stressful and disappointing time."

Police believe Carol Clay and Russell Hill were travelling together. They were last heard from on March 20, 2020. ( Supplied: Victoria Police )

Cause of fire unclear

Ms Clay rang a friend on March 19 and said she was going away and would return on March 29.

Their tent and campsite at Dry River track at Billabong, north of Licola, looked normal when it was spotted by other campers on March 26.

The pair was reported missing that same day, but on the following day their campsite was discovered torched.

The tent was destroyed in the fire but Mr Hill's four wheel drive utility parked nearby was in working order and had keys in it.

"Arson chemists haven't been able to determine a cause of the fire at this stage but we don't believe that fire was deliberately lit," Inspector Gaffee said.

"But there is a gap there between the 20th and the 26th so if anyone was up in the Wonnangatta Valley during that time period we'd love to hear from them."

Police were puzzled by the discovery of Mr Hill and Ms Clay's burnt out campsite and working vehicle. ( Supplied )

No evidence of foul play

Inspector Gaffee said there are a number of possible scenarios, some more likely than others.

"The more likely ones are that they are still in the valley, that a third person or parties are involved, or perhaps the people themselves have gone somewhere else," he said.

"But we haven't got the evidence to suggest that yet."

Police drones, helicopters and dogs have been used during the search, as well as mountain cattlemen on horseback and specialist State Emergency Service crews.

But the terrain is rugged, with cliff faces, steep hills and thick scrub, and rain late last week and over the weekend made access tracks unsafe.

Inspector Gaffee said some of Ms Clay's belongings were in the abandoned car, and food was left at the campsite so it looked like the pair had intended to return.

He said the pair had camped together previously and there was no evidence or information to suggest any foul play or third party intervention.

"I try not to work too much on gut feelings," he said.

"[I] try to let the evidence lead us to a conclusion, but unfortunately the evidence at this stage leads me to believe they are still in the Wonnangatta Valley and it's just a matter of time before we find them."

Inspector Craig Gaffee said access tracks to the search area became unsafe after rain. ( ABC Gippsland: Sarah Maunder )

CWA mourns past president

In a social media post, the Country Women's Association of Victoria Gippsland Hills group said it was deeply saddened by the unsolved mystery of Carol Clay's disappearance.

"Carol was a very much loved, admired and respected for her warmth, dedication and passion for CWA," the post read. "We will miss her very much. "We extend our deepest sympathy to Carol's family … and all her CWA friends in Victoria and around Australia and to the family of her travel companion, Russell Hill."

Two detectives from the Wellington crime investigation unit have been assigned to the case.

"Unfortunately with these sorts of cases it's not until it's solved that you get that final piece of the jigsaw that makes it all click," Inspector Gaffee said.