Ancestry has some NZ records you may wish to have a look at, including the birth index.
Electoral roll for Dunedin, 1946 - you may want to investigate possible family links between these households:
71 Maclaggan St
Ivan Henry Vivian, factory worker
Elizabeth Emma Vivian, married
131 Maclaggan St
Clarence St. Clair Vivian, labourer
Winifred Isabell Vivian, married
22 Wallace St
Bertha Vivian, widow
Constance Raemar Vivian, spinster
57 Prospect Bank
Thomas Errol Vivian, labourer
Margaret Ethel Vivian, married
12 Canongate
Georgina Vivian, widow