It's an eerie sight looking at the faces of 169 missing Australians listed on the Australian Federal Police (AFP) website.

The faces staring out are ghosts of the past, their faces reflect lives which suddenly froze the moment they vanished.

You expect them to be found as they are in the photos, still in their school uniforms, flares or stonewashed denim ready to pick up life where they left off.

One of the faces belongs to 31-year-old Lieutenant Sean Sargent who disappeared from the inner western suburb of St Lucia in March 1999 after going to a party with friends.

Sean served in the Defence Force for six years, attending the Australian Defence Force Academy in Canberra, studying electrical engineering and working with satellite communications.

At the party Sean was involved in a fight before returning to his friend's house on Orchid Ave in St Lucia where he said he would sleep in his car for the night.

Sean and his car have not been seen since.

Sean's father, Tom Sargent, from Mackay, said the hardest part was not knowing what had happened to his son.

"Its pretty devastating really, if you had some answers then it would be not so bad but you just know nothing," Mr Sargent said.

"We've had a lot of funny phone calls where people won't talk to us, police have traced them and they come from Canada, England, and even a place called Sao Tome off the West Coast of Africa.

"That's been happening off and on since he went missing.

"You tend not to believe that he is gone, I'm thoroughly convinced he's running around out there somewhere."

In Queensland each year almost 4000 people are reported missing. Most are found relatively quickly - less than 1% of people remain missing for any length of time.

Nineteen people are listed as long-term missing on the AFP Missing Person's site for Queensland with six disappearing from the Brisbane area.

"We find about 99 percent of all people that go missing," Senior Sergeant Jim Ryan said.

"Some people just don't get on with their families; others just want to make a new life for themselves."

Senior Sergeant Ryan said a missing loved one left families in limbo.

"They hear a car or the front gate or a knock on the door and they think it's the missing person who has come home," Senior Sergeant Ryan said.

"They look in crowds for them or wait for the phone to ring or even walk down the street and look for them."