Her sudden death on April 5 had left her family devastated and at a loss for words.
"Her family just want her back," Harrison said.
"The shock is huge. You can't really put it into words."
Rigg was the dearly loved wife of Peter and loved mum and mother-in-law to Matthew and Cindy, Christopher and Kelly.
She was also adored by her four grandchildren Claudia, Callum, Hope and Toby - all of whom had a "wonderful" relationship with their nana.
A tribute ride down the main street in Nelson will occur this Thursday to mark the day of her funeral and a last lap bell will be rung at the conclusion of that service.