Otago will meet Bay of Plenty, which won the event at Balmacewen last year, while Manawatu-Wanganui will play Wellington in the other semifinal.
Otago was unbeaten going into the final day but made things difficult with a 4-1 loss to Tasman yesterday morning.
For the second year in a row, Tasman ended Otago's unbeaten record, and Otago was left with plenty of work to do in the afternoon against Northland.
The Otago players responded, beating Northland 4-1, a margin which was sufficient for it to finish second.
Three teams finished with four points from six matches. Manawatu-Wanganui was top with 19.5 games and Otago second with 17 games, while Canterbury bowed out with 16.5 games.
After the morning disappointment, Otago came out strongly, as No 5 Mark Brooks started with three birdies to be 5-up after five holes.
He went on to post his fifth win for the week by an impressive 7 and 6 margin, at the expense of Northland reserve Brad Bonnington.
Otago No 4 Jamie Anstiss started slowly but increased his lead to four after 13 holes. Luke Brown fought back but Anstiss closed the match out 3 and 2 on the 16th green.
Otago No 3 Sean Masters was up against his former team and he opened up a lead of four over Chase McKeown after five holes.
McKeown fought back and Masters found himself only 1-up playing the 17th hole, which he birdied to finish the match.
Otago No 2 Nick Borren started eagle-birdie-birdie and was 5-up after seven holes but Lee Neumann played some superb golf in the middle of the round and Borren won with one hole to spare.
Otago No 1 Brent McEwan was up against New Zealand strokeplay champion Kadin Neho, who had just returned after competing in Argentina.
It was a close-fought match but McEwan could not defend his halfway lead, losing on the penultimate green.
In the morning, Otago made a horror start. McEwan and Borren were 2-down, while Masters and Kayne Wardell each lost three of the first four holes.
Only Brooks, at No 4, flew the flag at 2-up, which included a birdie three on the fourth hole.
Masters struggled off the tee and turned seven behind Hamish Campbell,who took every opportunity and scored 6-under-par for the front nine. The match finished on the 12th green, with Campbell 9-under to win 7 and 6.
It took the front nine for Wardell to find form but it was a tough ask after turning 6-down.
He fought back on the homeward nine winning the 11th, 12th and 14th holes but it was too little, too late and the match finished with three holes to spare. Brooks birdied the ninth to turn 4-up but this margin was halved when Tasman No 4 Nick Ludbrook won the 10th and 12th holes.
Brooks retaliated with three birdies to post a 5 and 3 win.
This left McEwan and Borren with the task of winning to keep Otago's record in place and both fought doggedly on the back nine.
Borren won the 10th, 13th and 15th holes to get back to square with Ryan Chisnall but he also went down by one, after three-putting on the final green.
After his slow start, McEwan birdied the last three holes of the outward nine to turn 1-down and the next four holes were halved in pars.
McEwan looked set to get back to square but Blair Riordan holed a 20m putt from the front of the 15th green, while McEwan missed his 3m putt. The match finished on the next hole, when McEwan missed the green and failed to get up and down.
Otago will face Bay of Plenty without Borren, who is best man for a good friend on the Kapiti Coast today.
