Samuels finished 35th in London in 2012. The 33-year-old enjoyed a breakthrough season in 2014, finishing the year in the top five on world rankings with consecutive podium finishes.
"I am very happy to be selected to go to Rio, it is always awesome to represent New Zealand but even more so at an Olympic Games. For me and my supporters we have spent the last four years working towards this, it has been no secret that since London I have been preparing for Rio, this has always been the goal, and to finish on the podium would be the ultimate.
"The course is a good strength course too and I think New Zealand athletes have a good record on strength courses, I think both Andrea and I are suited to this race, any day with a solid bike ride as part of the triathlon is a good one for us," she said.
Sissons spoke from Europe, where he is already based for the northern hemisphere season and his buildup to Rio.
"I am happy to be officially selected to the team after meeting the criteria in Abu Dhabi in March. I always dreamed of going to one Olympic Games but to make two is amazing.
"In some aspects the last six months have been very testing, I am especially happy to be there with Andrea, both of us would love to have had Laurent (Vidal) there but we are sure he will be looking down and supporting us, we will both be doing our best to make him proud.
"I am looking forward now to continuing the hard training and being in the best possible shape on the 18th August."
Triathlon New Zealand had earned three spots for the women in Rio under the International Triathlon Union (ITU) qualification system, but High Performance Manager Graeme Maw said the priority was to meet Tri NZ and NZOC selection standards.
"Today is about celebrating the achievements of four very proud and hardworking athletes who will delight in wearing the silver fern in Rio. I have no doubt with the support of their coaches, families and support staff, that Andrea, Nicky, Tony and Ryan will do all they can to achieve their goals and represent our sport with distinction."
New Zealand Olympic Committee CEO Kereyn Smith formally announced the team at and congratulated the selected athletes bound for Rio.
"Selection into the New Zealand Olympic Team is a significant achievement and while today is a celebration, the athletes can now knuckle down and focus on final Rio preparations,
"We wish these four athletes all the very best as they enter their final stages of preparation and look forward to cheering them on at the Olympic Games in August," said Smith.
Maw also noted the tough criteria set by both Triathlon New Zealand and the NZOC for selection and congratulated the athletes on reaching these targets.
"We set out with challenging selection standards and are delighted to have four athletes who have met that criteria and are ready to chase their goals in Rio. The selectors are confident to go forward with those four athletes to achieve the team's goals and wanted to also acknowledge the genuine efforts of other athletes who were striving to make the team and wish them well in the future," he said.
Two-time Olympic medalist Bevan Docherty sat on Triathlon New Zealand's Elite Selection Commission, he spoke of seeing the process play out from 'the other side'.
"It has been quite reassuring to know there is a tough but fair and robust policy in place. I probably wasn't aware of the process when I was an athlete, but now I have been through it I can reassure everyone of a fair and honest selection process.
"It was very clear to us (Selection Commission) the athletes who had met the criteria, the athletes knew what they had to achieve and the benchmarks were set quite high, but as the level of competition in triathlon is rising and getting harder and faster, the policy is meeting that challenge as well.
"Just qualifying is a huge step in any Olympic campaign, to those named today it may be a huge relief that will allow them to put their heads down, train hard and focus towards the big day, I am sure they are super happy but there is a lot of hard work ahead of them."
Chief Executive of High Performance Sport New Zealand Alex Baumann also congratulated the four selected athletes named today and noted the level of talent in the team.
"We believe this is one of our most exciting triathlon teams to be selected for an Olympics. I am delighted to see our investment in the programme reflected through the pipeline of talent selected today and I would like to congratulate all the athletes and acknowledge their hard work and dedication," he said.
With 72 days remaining until the Olympic Games kick off on August 5, the New Zealand Team now stands at 84 athletes and this number looks set to grow with several team sports due to be announced in the coming weeks.
In Rio both the women's and men's triathlons will take place at Fort Copacabana, with 55 athletes in each event. The men's triathlon is scheduled for Thursday 18 August and the women's race will take place on Saturday 20 August.
