"It's like you put a wet blanket over everything," Mr Castor explained.

Speaking from his home in Sweden, Mr Castor said he still held hope that his son Max, who was last sighted in Warrnambool five years ago, would one day return home to his family.

"My position today is that he lives a good life in your country."

Max disappeared on April 1, 2005 during a back-packing trip around Australia.

After lasy being sighted in Warrnambool, there were several unconfirmed sightings of the then 25-year-old along the Great Ocean Road and into the Otways, but his last known contact with his family was on April 21, 2005, when he sent an email to his family.

On the same day his brother in Sweden received a parcel containing Max's personal belongings, money and a letter.

He was last seen wearing a blue windcheater, white t-shirt, jeans and carrying a light blue backpack and a multi coloured clutch bag.

The case has been highlighted as part of National Missing Persons Week in the hopes that new information may come to light.

His father told The Standard that he spent the first few years actively looking for Max with the support of the Victorian police force, the Swedish embassy and consulates, the Swedish church abroad, the Salvation Army and many individuals.

"None of this have given any result and, to keep my mind healthy, I have changed position a little.

"So today, Max comes up in my head a few times a week and, especially when I visit places connected to Max, I may get a little moist in the eye wrinkle."

Mr Castor said he acknowledged that Max was an adult who, for some reason, had chosen to break contact with his family and friends.

His search now revolves around contacting Swedish tourists planning a long-term stay in Australia and who are about the same age as Max, asking them to keep their eyes open.

"Maybe 100 to 150 have been contacted and maybe some have seen Max but they were not quite sure.

"Somewhere along the east coast (one) went out for food and was joined by a man, obviously a Swede looking like Max, but not talking about himself ."

Mr Castor said his family often spoke about Max: "We have somewhat different opinions about what happened."

"A peculiar feeling is Max's niece and nephew, who were born after we lost contact, slowly getting aware that they have an uncle and asking questions like where does he eat, where does he sleep (and) does he have a blanket and pillow?

"(These are) important questions when you are three or four years old."

But what does Mr Castor believe of Max's fate?

"My opinion is that he is alive, living in some kind alternative non-commercial society practising some craft.

"Max is very clever in learning practical skills and crafts he picked up a lot from my grandfather and myself, like painting, gardening woodworking (and) work at the anvil.

All (of this) is so obvious to him you just need to show (him) once and then he masters and improves.

Mr Castor believes Max has probably changed his name as he has no valid visa in Australia. He also thinks he may be living in a relationship and may have a child as he was very fond of children.

He realises that his son may be keeping a low-profile: "He is aware that I have been looking and that if he passes a border, the interpol alarm system may sound."

"I check with his friends now and then and most believe he is alive but they are a little concerned that they have not heard anything.

"Then, of course, there is the possibility of a desert accident like a poisonous snake or thirst. He is trained in outdoor living, but your nature may be harder than ours or unfamiliar."

He hopes that as Max gets older he will one day contact his family in Sweden - perhaps as his own children start questioning their background.

Mr Castor is now praying that he will still be alive himself to see that day.