Hailing from Sweden and South Africa, the new citizens swore an oath of allegiance to the Queen and to observe New Zealand law before being presented with citizenship certificates and flax plants by Mayor John Booth and Deputy Mayor Elaine Brazendale.
Mr Booth said he looked forward to the contributions the new citizens would make to the community.
"We are very, very proud of what we have achieved and what we are achieving now and some of you will be the ones that help us to achieve in the future."
Mrs Jacobs, who moved to New Zealand with her husband and daughter six years ago from a rural town not far from Cape Town, said the family chose New Zealand after hearing positive feedback from other South Africans.
The family moved to Carterton from Hamilton about a year ago.
"I love the quietness - just the family feel that you get here. It's a nice, quiet, tranquil place and everybody knows everybody."
However, the ceremony was bittersweet as the family would soon be relocating to Palmerston North, where her husband was employed as a chef, Mrs Jacobs said.
Long-time New Zealand resident Mrs Harper, who was born in Sweden, said she made the decision to become a citizen for practical reasons.
She moved to Carterton in 1994 and loved the rural lifestyle, she said.
"I was brought up in an apartment but I've always loved animals and farming."
She and her husband have an 80 hectare farm in Gladstone.
