"The two-day event attracts around 5000 competitors, 13,500 supporters and attracts media from all four corners of the globe," Trewavas said.
"This is as big as it is ever going to get. We are talking the best of the best," he said.
The professional women and age-group women would race on one day and the professional men and age-group men would race the next.
Taupō District Council had committed $478,000 to attract the event and had been successful in attracting a government investment of $975,000 from the Major Event Development Fund. About $100,000 of the council's commitment would be "in kind" for infrastructure, venue use and other support.
Trewavas said the council had made it very clear that economic development was a key part of achieving its vision of being the most liveable and prosperous district in the North Island by 2022.
"Winning the hosting rights for this event not only re-emphasises that our district is the Events Capital, but it also further cements Taupō as being the home of all things Ironman in New Zealand."
District events manager Steve Giles said operationally the council was confident the community not only had what it took to host an event this size, but that it would be one to remember for the 14,000 international and 4300 domestic visitors it would attract as well as the likely tens of thousands of spectators.
"In Ironman circles, this is equivalent to the Rugby World Cup or Americas Cup so we have the opportunity to deliver something really special," he said. "This will give our community a chance to not only to volunteer in an international event, but also to showcase our district like never before."
The Taupō District will be promoted to about 190,000 athletes at more than 120 events in the global series as they vie for a spot at the 2020 Ironman 70.3 World Championship from July next year.