SEARCH and rescue dogs will on Tuesday join the operation to find a couple missing on Mount Buffalo.
The specialist canines will link with up to 150 people in the hunt for Trevor Salvado and his wife Cindy Bohan who were last seen on Friday morning.
Police Inspector Joy Arbuthnot said the dogs had not been used earlier because the number of Labour Day weekend trekkers on the peak would have complicated their detection task.
She said the search would centre on a radius of a 1000 to 1500 metres from the couple's car found at the Reservoir track car park beyond the chalet.
The pair's son Nathan Salvado, 21, and Ms Bohan's sister Maria Bohan said at the search site on Monday they were hopeful of a happy ending.
"Cindy is one of nine and I'm her big sister, so we're all hanging together with Cindy and Trevor's children, Isaac, Nathan and Rachael, and we hope that they are safe and that they are found really, really soon," Ms Bohan said.
She said the Melbourne couple had spent the past eight years visiting the Ovens Valley with other couples and their children and they arrived at the Bright caravan park at different times.
"Cindy and Trevor are super fit, they're very healthy, they're used to being out for hours...they spend a lot of time outside," Ms Bohan said.
Nathan Salvado said he was alerted to his parents' disappearance via a text message from one of their friends stating they had not been seen at the camping ground.
"I just want them to be warm and safe," he said.
"They're pretty responsible walkers, they know what they have to do survive."
Mr Salvado said his father was a cyclist and paraglider, while his mother enjoyed stand-up paddle boarding.
Ms Bohan said their hopes and "good old-fashioned prayers" were buoyed by the emergency services commitment to the search.
"It's bloody impressive," she said of the police operation.
"That gives us lots and lots of confidence.
"As a big family we want to thank all the people who are working here in (a) volunteer capacity and who've come from miles and miles to do that."
SES members from as far away as Kinglake and Numurkah joined North East crews in the search yesterday.
In addition to police and SES, specialist bush rescuers, Parks Victoria and state environment and health departments are part of the search.
The search is due to resume at 8am on Tuesday.