The family of an elderly Tasmanian man missing for five years has still not given up hope.

Nicola Sallese had early onset dementia when he went missing in November 2008.

The Sheffield man's silver Toyota Camry has never been found.

His family has again appealed to the public for assistance as part of National Missing Persons Week.

Son Jason Sallese says the family still holds onto hope.

"All the families do, what they can, and it is good that there is a week set aside for missing persons and it just gets the word out there," he said.

"If it helps just one family, ourselves, somebody else, it would be a good result."

As part of this year's message police are urging people with mental health issues to seek support.

Police say people with early signs of depression or other forms of mental illness can go missing if they feel unsupported.

Senior Constable Natalie McIntee says people should not wait to report a person missing.

"Going missing is not a crime," she said.

"We would like to make that clear to anyone who is out there , who thinks they may be a missing person or knows that they are, that going missing is not a crime and please contact police or family as soon as you can."