Her father, aunt and cousin all reached 100 years old and Mrs Mckenzie joined them this week.
"We’re all hoping we’ve caught the right gene," her daughter Sharyn Walker said at her birthday celebration at Observatory Village rest-home in Oamaru on Thursday.
Mrs McKenzie told the Otago Daily Times it was just "like any other day".
"I never thought I’d become 100."
She was born in Balclutha and grew up in Clydevale.
There she met her future husband Ken, who was a shearer.
The couple married in 1945 and enjoyed more than 50 years together before Ken died.
They owned a 28ha farm in Weston and raised four daughters.
Mrs McKenzie also has six grandchildren and 10 great-grandchildren.
She used to be an avid baker and also enjoyed an illustrious bowls career in North Otago.
She picked up the sport while in her 30s and kept playing until she was nearly 90, winning 12 North Otago centre titles.
Mrs McKenzie celebrated her 100th birthday at a lunch with her four daughters and was expecting extended family and friends today for a larger party.
