The Northern Territory Coroner will re-open the inquest into the mysterious disappearance of Patrick "Paddy" Moriarty in the outback town of Larrimah, 500 kilometres south-east of Darwin.
Mr Moriarty, 70, and his cattle dog Kellie went missing just before Christmas in 2017.
The tiny outback town of Larrimah at the time of Mr Moriarty's disappearance was home to just 12 people.
Mr Moriarty's disappearance sparked a widespread police investigation and part-heard coronial inquest in June 2018.
The ABC understands the final part of the coronial inquest, set for two to three days from April 6, will examine police investigations since the time of the last inquest almost four years ago.
The coroner will call witnesses to the Katherine Local Court to give evidence.
Police last year offered a $250,000 reward for information about Mr Moriarty's disappearance, believing the outback Irishman had been murdered.
Witnesses told the coronial inquest in 2018 Mr Moriarty was a "happy-go-lucky" man embroiled in a deep feud with a neighbour.
The inquest heard the owner of a local Larrimah pie shop had threatened to kill him.
Mr Moriarty's car and quad bike were left behind when he disappeared, and food had been left out.
The mysterious circumstances of the disappearance sparked intense media coverage, with a podcast, ABC web series and book published in the years since.
"Someone out there knows what happened," said Detective Sergeant Matthew Allen in 2021.
"We want them to come forward and help us solve a murder.
"You may be eligible for immunity from prosecution."
Mr Allen said in a pre-recorded video in 2021 some persons of interest were "stronger" than others.
The inquest will return on April 6 in Katherine.
