There have been four potential sightings of a 72-year-old Melbourne man feared missing on Mount Buller.

Police have revealed Conrad Whitlock may have been walking dazed and confused down the mountain hours after arriving.

The search for Mr Whitlock is entering its third day, with crews expanding their catchment from the spot where his BMW was found on Tuesday.

Missing Melbourne man Conrad Whitlock. (Supplied)

Four people have said they saw a man matching his description walking beside the road about 9am that day.

Despite the fearsome weather conditions, Graham Gales from the SES is optimistic about finding Mr Whitlock alive.

"We're not looking for anything else but to find him fit and well," he said.

Mr Whitlock had been suffering headaches, his wife revealed yesterday, and police are fearful it prompted his unannounced departure from his Melbourne home.

Police found Conrad Whitlock's BMW near Mount Buller Ski Resort in the Victorian Alps. (AAP)

"We've been married for 52 years and I can't comprehend that he would do anything so out of character," Mrs Whitlock told media yesterday.

"All I can think is there is something wrong with the headaches – I don't know if he has had a mini-stroke and is wandering around with amnesia, I don't know. Just not knowing is the worst part," Ms Whitlock said.