Ms Chapman, nee Hanson, celebrated her milestone birthday with family and friends at Redroofs Lifecare in Māori Hill yesterday.
Speeches and songs from her daughter, Phyll Esplin, were followed by afternoon tea and a glass of white wine.
Ms Chapman was born in Huddersfield, England, in 1924 and arrived in New Zealand on the Captain Cook in 1958 with her family.
Ms Esplin remembered what a culture shock it was for her.
"Life here was slower, shops were not open on Saturdays, there was Friday night closing and nothing opened until Monday morning.
"It was quite different from the life we had left behind."
Ms Chapman and her family moved into a house that was only five years old in Kaikorai Valley and she lived there until she moved to Redroofs when her husband died in 2022.
Ms Esplin said her mother reaching 100 was testament to her determination to live.
"Irene was a proud woman and leader," she said.
During World War 2, a friend convinced Ms Chapman to train with the auxiliary territorial services in the British army.
She was sent to York as a clerk and paid soldiers’ wages.
She was also assigned to picket duty and her job was to put out firebombs as quickly as she could.
"The thing that hurt the most was losing those around you that you knew," Ms Chapman said.
Ms Chapman has one daughter, one son and six grandchildren.
