Organisers of the World Triathlon Grand Final are expecting 50,000 specators a day at the event in Auckland this weekend.
It is the biggest sporting occasion in New Zealand since the Rugby World Cup, with 3000 athletes from 45 countries competing.
The events include elite men's and women's, amateur age groupings and a Para-triathlon competition.
New Zealand has the biggest team at about 750 strong; many of whom took part in the Thursday's opening ceremony on Auckland's waterfront.
The event will dominate Auckland's central city over Labour Weekend, with a number of streets in the central city closed for races, and buses will be re-routed.