The competition, due to kick off on Saturday, will involve 12 teams from around the Highlanders region.
Otago Boys, Kings, Kavanagh, John McGlashan, Dunstan and South Otago are the six Otago schools included, while Southland Boys, Verdon, Central Southland and Gore are the four Southland teams.
Waitaki Boys and St Kevins are the teams from North Otago.
Seven teams were nominated from Otago for the competition, and results over the past three years were analysed to see which teams would qualify.
That resulted in a play-off between John McGlashan and Taieri College a few weeks ago, won by John McGlashan, 29-5.
Otago Rugby Football Union amateur rugby manager Justin Gardner said the competition had been mooted for years.
It would cost $100,000 to run, with 95% of those costs for travel.
The competition is sponsored by the Southern Institute of Technology, with the Otago Daily Times an associate sponsor.
Sponsorship covered two-thirds of costs, with the rest being met by the schools.
The competition will start with a full round-robin, to be followed by a top four, middle four and bottom four.
The final will be played on August 22.
All traditional interschool matches will be played within the competition and have been organised to be played as close as possible to the date when the rest of the interschool sports exchange is played.
Gardner said the Otago schools under-18 competition, including other school teams, will continue, and positions are not fixed.
The bottom team in each union can be challenged by the top team in the under-18 schools competition next year.
But only one team per school can be in the top competition.
Gardner said all other Super 14 franchises in New Zealand had similar competitions and that had improved the standard of schoolboy rugby.
He hoped the new competition would have the same result here.
Players and coaches were excited about the competition and hopefully it would lead to a higher representation in the South Island secondary schools team, Gardner said.
The competition starts on Saturday with Otago Boys playing John McGlashan, Kings playing Verdon, Kavanagh against South Otago, Southland Boys playing Central Southland, St Kevins taking on Dunstan and Gore playing Waitaki Boys.
