The competition will take place at the Waitaki Aquatic Centre. Teams are expected from as far away as Nelson and Invercargill.
Waitaki Aquatic Centre Manager Matthew Lanyon said 26 teams would be competing and Oamaru would experience an influx of teenagers and adult supporters over the weekend of August 7 to 9.
''It is shaping up to be one of the biggest tournaments in recent years. We have been working closely with organisers over a number of months to bring this event to Oamaru.''
That included arranging accommodation, as well as suggesting activities and attractions for the competitors around Oamaru.
The tournament was likely to draw more than 250 people to Oamaru, bringing significant economic benefits.
The main pool will be closed from 6pm on Friday, August 7 to 3pm Sunday, but the children's pool and spa pool will remain open.
''This is a great opportunity for people to come and see a sport that is not often seen outside main centres,'' Mr Lanyon said.
Teams representing their schools from around the South Island compete at regional qualification tournaments to earn entry to the New Zealand championships.
The top teams from each of the qualification events are eligible to contest under-15 years, under-19 division 1 and under-19 division 2 categories at the national event.
