"Morgan was my dad and I've always meant to come and mark the site of his grave and now finally, we've done it," Rosaleen Nearey, of Carterton, said.
Mrs Nearey's husband Graeme has always been interested in the family history and had carried out some research, before his daughter Eireann took over.
"I've been able to search Papers Past to find out about my great grandfather," she said.
A report in newspapers at the time described how Mr O'Flaherty, 46, had died on the Taikoiu-Karetu Rd near Weber.
A road overseer foreman, Mr O'Flaherty was working on a scoop when he was thrown over an embankment and fell more than 12m. He died a few minutes later.
With details of his burial place, grave 33 in block E, Mr O'Flaherty's descendants were able to trace the exact site of his grave, thanks to the map at the entrance to the Settlers Cemetery.
"My mum still feels very Irish and is very proud of her roots and it's been wonderful to finally mark my great grandfather's grave," Mrs Dempsey said.
Mrs Nearey has ensured there is a link between her home town and her father's grave in Dannevirke, with a ring cut from a 100-year-old tree in Carterton encircling the wooden cross on his grave.
Mr O'Flaherty also had a connection to the founder of the brewery at Mangatainoka, Henry Wagstaff. The brewer was fined 170 and forced to forfeit his brewery plant for four breaches of the Beer Duty Act after the customs authorities of the time brought the charge on the information of Mr O'Flaherty, his great granddaughter said.
"He complained about cloudy beer and knew how these things worked as he'd been a policeman," she said
However, Mr O'Flaherty admitted under cross examination that if Mr Wagstaff had paid him 25 hush money as demanded, he wouldn't have informed, a report in the Bush Advocate on February 8, 1896 said.