While Dr Sinclair had lived in New Zealand for most of her life, she said she chose to become a citizen now for a few reasons.
"I'm certainly very proud of the existing New Zealand Government and their principles of social justice," she said.
"It seemed a good time for me to become a New Zealand citizen. I'm proud of what our future is going to be under this government.
"I like the direction the country is heading."
Dr Sinclair said she loved Rotorua.
"I'm proud of having lived in Rotorua. It's a very grounded and multi-cultural community."
Dr Sinclair said her children's upbringing in Rotorua also meant they were welcoming of all cultures and she was happy to have raised her children to be the way they were.