DEMENTIA will be highlighted during National Missing Persons Week, which starts today.
There are 157 long-term missing people in Tasmania, dating back to 1955, including people lost at sea.
About 95 per cent of missing persons cases are solved within a few days.
Last financial year, 110 people went missing in Tasmania and five were not located.
Senior Constable Natalie McIntee, co-ordinator of the Tasmania Police Missing Persons Unit, said dementia was often a factor when people went missing, especially among older people.
Mild dementia sufferer Nicola "Nick" Sallese, born in 1939, went missing from his home town of Sheffield in November 2008.
He was believed to have been driving his silver Toyota Camry sedan, registration FH2973, which has never been found.
Possible sightings of the Italian-born Mr Sallese were reported across the state.
Senior Constable McIntee said the Sallese family accepted that their beloved father and grandfather was probably dead, but remained hopeful of finding out what happened to him.
"The sooner a person is reported missing, the better chance we have of locating them," she said.
"Don't wait 24 hours before reporting someone missing.
"As soon as you have concerns for their safety, report it.
"When the very old, very young or those suffering an illness go missing, minutes count."
In Tasmania, about six per cent of people reported missing are aged over 65.
The rate of moderate to severe dementia in Australia is one in 15 people over the age of 65.
Senior Constable McIntee said the elderly and those with dementia, people with mental health issues, and youth, were the three key groups most likely at risk of going missing.
"In Tasmania, accidents also contribute - lost at sea or lost in the bush," she said.