Quinn Martin was a kind, caring father and a hard worker, his partner Jana says.
Late on a Friday night in 2012, he was working at the back of his sprawling property in Colo Heights, north-west of Sydney, just metres from Jana and his two of children, when he simply vanished.
After almost three years of exhaustive investigations, police conceded on Friday that they had found absolutely no trace of Mr Martin.
"The pain my family has gone through since that time is indescribable," Jana said on Friday as she made a plea for public assistance.
"I would never wish any other family to go through what we have gone through since the disappearance."
Mr Martin, Jana and two of their five children had travelled by ute to a remote part of their property in the Hawkesbury region to carry out some maintenance work on the evening of December 7, 2012.
His wife and children played in a farmhouse while Mr Martin, 35, tended to the property, telling them he would be back to drive them back to the main house.
"They had a conversation about work he was doing ... and that he would be back at a certain time," Detective Inspector Paul McHugh from Hawkesbury police said.
"But he never came back."
There has been no trace of Mr Martin since then. His bank accounts have not been touched and an extensive search of the property and wider bushland found nothing.
Initially, there was a suggestion that Mr Martin was seen about 2am walking on the Putty Road at Colo Heights, possibly to a friend's house.
However, Detective Inspector McHugh said that police were never able to confirm this nor establish who the friend may have been.
He said Mr Martin was well known in the South Windsor area, having lived there for 15 years, and it is likely someone may have seen him since his disappearance.
Police have no idea if he is still alive or has met with foul play.
"We haven't got anything concrete," Detective Inspector McHugh said.
"We have [followed] numerous lines of inquiries but ... at this point in time, we are still no better down the track in terms of the investigation."
He pleaded with anyone who may have seen Mr Martin or know anything to contact police anonymously.
Jana said Mr Martin was "a kind and caring father, a hard worker and an important part of our family".
"After almost three years of not knowing what's happened, I ask today if anyone has seen Quinn or may have seen him after his disappearance, no matter how insignificant you believe the information you have is, please come forward."
It is believed Mr Martin could have travelled to a number of areas, including the Far North Coast of NSW where he had some family connections, Coffs Harbour, Corindi, Grafton, Maroochydore or Hervey Bay.
He is described as being Caucasian, about 180-190 centimetres tall, of solid build, with short blond hair and blue eyes.
He was last seen wearing light-grey cargo shorts, work boots and a flannelette shirt.
Anyone with information should call CrimeStoppers on 1800 333 000.
