Only 11 of last year's team - which finished last in the league - will be back and the loss of key players such as striker Tom Jackson, midfielder Eder Franchini, defender Cam Attwood and striker Taylor McCormack has forced some of the changes.
Coach Mike Fridge is in the process of confirming several transfers and said he would not name the squad until all 22 players were signed up.
A former Canterbury midfielder, who has been playing in Australia, is rumoured to be joining the team.
''We weren't allowed to sign any players until October 1,'' Fridge said.
''We sent through all the transfer requests, and right now they're not officially signed with us. I'm hoping all these transfers will go through very quickly and we can announce the squad.''
Some of the new players Fridge will name in the squad are from Auckland, while some Dunedin players who were not available a year ago are expected to come in, at the cost of others.
''There are one or two players I've decided not to go for this year. We've brought in some new players, we've tried to revamp things,'' he said.
The 22-strong squad must be registered with New Zealand Football by November 4.
Training started last week and Fridge is expected to put the players through their paces three times a week before the season opener against Waitakere United in Dunedin on November 15.
Southern United will play a warm-up match in Invercargill against an invitational team next Saturday and a pre-season match against Canterbury United in Timaru on October 31.
There are also plans for a couple of friendlies against the Southern United youth team. Fridge is looking forward to the season, which includes six of Southern United's games being televised live on Sky Sport.
''I think it's great for football in New Zealand,'' he said.
''We're involved in six, which is fantastic. We play our home games at Forsyth Barr, which is also great.
''It is top-flight football in the country, so I'm looking forward to it.''
