There were five examples of babies given each of the names in Otago last year, according to birth notices published in the Otago Daily Times.
Ruby, Georgia, Emily, and Lucy were the next most popular girls' names, with four of each.
In five years' time Otago primary school classrooms are also likely to feature boys by the names of George and Max, with the names tying for the next most popular boys' name (both four).
Candice and Jason Ross-Fraser, of Momona, named their son Arlo, born April 1 weighing 2.47kg (5lb 7oz), because they wanted "something unusual'' but easy to say.
Mrs Fraser-Ross was not disappointed to hear her son's name was not so unusual after all. He had two middle names, Sandy and Drew, which he could use if he preferred.
St Kilda tot Isla Mae Stewart, born on September 6, to Kirstin Lammers and Shane Stewart and weighing 3.43kg (7lb 9oz), was almost named Ellie.
Had Isla been an Ellie she would have been the only one out of 281 birth notices.
Her 5-year-old brother Luka's toy elephant already having the name meant Isla was chosen, Ms Lammers said.
Last year' top Otago names bucked the national trend. While Isla was the third most popular girls' name according to the Department of Internal Affairs, neither Arlo nor Henry featured in the national top 10 boys' names.
Olivia and Oliver were the most popular names for the second year running.
Notable omissions in the birth notices included Sarah, Amy, David and John. The once popular names did not feature at all in Otago birth notices.
More unusual names included Ambrose, Bodhi, Edison, Mazzlin and Ziva.
