Otago finished in second place with 2.5 points and 21 games leaving Canterbury in third place with two points and 16.5 games.
Southland defended the South Island title it won last year and is now on target to defend the national Toro title at Balmacewen in December which it won in Gisborne last year.
Although Southland will be without New Zealand No 1 Vaughan McCall, who has received an invitation to compete in the Australian Open in December, the top five who played this weekend showed they have the ability to make it two in a row.
Individual results showed the secret to Southland's win with No 3 Scott Hellier the only one of the forty golfers to post four wins. He was supported by Jeremy Hall (No 4) with three wins and a half while No 8 Daniel Mills was also unbeaten with two wins and two halves.
For Otago, Brent McEwan (No 1), Mark Collie (No 6) and Kayne Wardell (No 7) all emerged unbeaten with three wins and a half each.
Other unbeaten players were Oscar Cadenhead, Michael McAuley (both Canterbury) and former Balmacewen junior Thomas Facer who played at No 7 for Tasman.
Despite finishing second, it was a poor start on Saturday morning which put Otago out of contention.
At lunch, Otago trailed Southland by a 1 to 3 margin and Tasman by a 1.5 to 2.5 margin.
The team improved dramatically in the afternoon but were playing catch-up.
Three wins from four got a half with Southland with Otago the only team not to be beaten by our southern rival.
But in the final match against Tasman, Otago's Samson Kim was deprived of a half with a precarious bunker shot on the final hole which bounced high but finished well.
After a shaky start on Saturday, newcomers Brandon Hodgson, Samson Kim and Jamie Anstiss had a good day yesterday with five wins and a half for the trio.
Mark Collie (No 6) pushed for a place in the final five as did Kayne Wardell (No 7) who had two 14-hole wins against Aorangi and Canterbury yesterday.
• Ian Poulter carded a final round of 65 to seal a two-shot victory in the HSBC-WGC Champions Tournament at Missions Hills in Shenzhen, China, last night, Reuters reported.
Poulter started his final round four shots behind joint leaders Louis Oosthuizen and Lee Westwood, but clawed his way to the top after matching the 7-under-par 65 he shot a day earlier to finish on a combined 21 under.
Poulter finished two strokes ahead of South African Ernie Els (67) and United States trio Jason Dufner (64), Scott Piercy (65) and Phil Mickelson (68).
Westwood and Oosthuizen finished tied for sixth, three shots adrift, after carding matching level par 72s.
