Football South released the proposal for the competition to its clubs yesterday, following a meeting with Mainland Football in Timaru last week.
The proposed league could start as early as next year and would include teams from each federation.
Football South CEO Chris Wright said there were "a few elements" to the proposal, but a possible breakdown could have three southern clubs joining four from Christchurch and one from Nelson.
Options would be put to the clubs on how it would work and they would indicate their preferences.
In one possible scenario, the local competition would be played as usual for the first round, then the top teams would move into the South Island league and the others remain in the local league.
Another option could be to go for full-on separate leagues that started and finished with the same clubs. That could be "quite a big stretch" financially.
Wright said the main aim to start with was to get more games against high-quality competition for the teams at the top of the table.
From there, it could be developed into something bigger.
The clubs had been supportive and the idea of the league was one of the most regular things that had been asked of Wright since he began his role 18 months ago.
There had been concerns around financial and travel issues, although Wright believed the proposal looked to minimise those the best it could.
"I think there’s a mixture of things going on to ensure financially it is viable.
"The structure of the proposed competition, it’s not a 20-team league, or 10 teams playing each other twice.
"The main proposal is eight teams with one round, so it’s seven games per team, which is far more viable.
"Just through some investment in Football South, some other funding, sponsorship, things like that, we hope we can make it as viable as possible.
"Having the cost equalised across the teams is important as well, because places like Nelson or Queenstown or Southland are going to find it far more expensive if they have to fund the direct costs all themselves."
By exposing the region to the top Mainland teams, it was hoped to develop the sport in the South.
That would have flow-on effects on the national league, as it would help bridge the gap that meant players took a large step up at the moment.
"The aim is to get our best senior and youth players competing at the highest level as possible, providing our coaches and players and referees and clubs that opportunity to continually improve and develop. So that’s the whole aim and purpose of the competition.
"If we achieve that, certainly we’ll be very happy."
