Fiona Wills, who disappeared without a trace almost three months ago, will be remembered in a memorial service later this month.
The 77-year-old Alzheimer's sufferer is presumed dead after she vanished from Trelinnoe Station homestead in Te Pohue on December 9.
Read more - Wills family still searching for clues
Wills Family still at a loss over missing mother.
She is understood to have gone on a routine walk to feed her chickens in the fowlhouse, about 50 metres from the house.
A series of painstaking searches of the area in the ensuing weeks, including the use of dogs trained to find bodies, yielded no clues - not even the plastic jug she had used to feed the chickens.
Her son, immediate-past Federated Farmers national president Bruce Wills, said he would go to his grave knowing he did all he could to find his mother.
The family had decided to hold the memorial after a "final push" to find Ms Wills last month, which involved a search party of more than 100 people led by internationally renowned search and rescue expert Ross Gordon.
"There does come a time where we've got to let her rest in peace and move on. [The memorial] will be a time to remember, a time to reflect. It's a bit of closure for the family."
However, he would always keep an eye out for any sign of Ms Wills.
"We'll never stop looking. I guess we'll always wonder until the mystery is solved."
The memorial service for Ms Wills will be held at Trelinnoe Gardens on Saturday, March 14 at 11am.