Evelyn Middlemiss celebrated the big day with family at Chatsford retirement village in Mosgiel.
Asked how it was to be 100, Mrs Middlemiss said she felt like she was only just starting.
She was born in Timaru and brought up in the Mackenzie Country, where she enjoyed a quiet life.
''I was born to that country and I grew up there.''
Her entire schooling was by correspondence.
She could have boarded with family members at Timaru or Christchurch but enjoyed learning from a distance.
''I had a lot of time for that correspondence school.''
A well-tuned harp player, Mrs Middlemiss recalled her first public performance was at the Dunedin Town Hall.
Mrs Middlemiss enjoyed her time on the farm with the animals and attributed her longevity to living a quiet life in the high country.
''We were so lucky.''
She also managed to avoid going to parties.
''I don't think I went to a party in my life. We weren't that sort of family.''
During World War 2, she worked for jet-boat pioneer Bill Hamilton at Irishman Creek station near Lake Tekapo.
She was proud to say she drove the first jet-boat around the dam there.
Mrs Middlemiss could operate a lathe and was known for her meticulous work in the engineering shop. It is believed she performed more than 15,000 operations on the lathe.
''They stopped me doing it as I wore it out,'' she said.
She survives her husband, Don, whom she married at the Church of the Good Shepherd in Lake Tekapo.
Mrs Middlemiss had one daughter, Raewyn, who gave her two grandchildren and four great-grandchildren.
