Otago Medical School alumni Bryden and Ella Nicholas will compete in canoe slalom events over the next few days.
Bryden will compete in the K1 men’s class, while sister Ella will appear at her second Olympics in the K1 women’s’s category, having also paddled at the 2012 London Games.
Ella will also be the Cook Islands team flag-bearer at today’s opening ceremony.
"It’s very special. I was brought up as both a Cook Islander and a Kiwi and I have very strong links to both countries," Ella said.
"However, the Cook Islands are very small and very unique. We are one of the smallest teams at the Games and most people have no idea where we are from, or that the Cooks even exist.
"It is a privilege to be able to educate them on this and tell them all about our little piece of paradise."
Ella started work as a junior doctor in November last year but is on leave so she can train and compete at the Games.
She graduated bachelor of medicine and bachelor of surgery in 2015. Bryden received the same qualifications in 2012.
Ella and Bryden’s younger sister Jane, who will graduate from Otago Medical School in December, is also a canoeist.
She represented New Zealand in the K1 and C1 divisions at events in Europe in June.
The three siblings are the cousin of another former University of Otago student and local sporting representative, former Otago and Highlanders rugby player Ryan Nicholas.
The men’s canoe slalom takes place on Monday morning, while the women’s event will be held on Tuesday morning.