North Otago will travel to Greymouth for the second time in three weeks for the final against West Coast, which thumped Buller in the other semifinal.
North Otago started in impressive fashion with the northeasterly at its back, denying King Country possession for the first five minutes before the visitors found their feet.
First five-eighth Daniel Waenga was North Otago's man of the match, scoring 26 the team's 31 points and taking his points tally in Heartland rugby to 102 for the season.
Taua Limuloa and Palenapa Mafi stood out in the North Otago pack, the former taking some superb line-out ball, including several snaffles against the throw, and showing mobility in the loose. Loosehead prop Mafi, coming back from injury, was in everything and set up Waenga's second-half try with some diligent chasing.
Young David Simpson showed his versatility after being thrust into lock, having come off the bench as a No 6 in previous games. King Country had a star out on the right wing in big Fijian Rupeni Seduadua, who was given latitude in the final quarter and ran in a hat trick of tries as King Country surged back.
His chances were set up by some superb distribution from second five-eighth Kane Quinlan, the mastermind in the King Country midfield whose ability to create space served his side well.
Sam Mason was a fiery No 6 but the King Country pack without Aaron Dunster and Jamarl Hone, its two regular locks, was too often under pressure in the scrum. North Otago player-coach Mike Mullins described a sense of relief at the final whistle.
"We just hung on.
We said we'd take the win and we've got it, so we're in the final.
That was our objective, so the planning starts now for our next weekend in Greymouth."
North Otago made its best start of the season, which pleased Mullins. "It was just a matter of us trying to get some structure back into our game, I think.
We just had too many isolated runners around the 22 area, but once we got numbers around the ball then holes started to appear for us.
"Late in the game we fell away in the last 10 minutes and we just managed to hang on . . . but we're just happy with the win.
Happy we eventually got some structure through our game and got numbers to the rucks and maintained possession.
If we do that a bit more we can put on points."
A feature of the game was the return to the field of former North Otago captain and midfielder Mike Mavor, who came out of retirement on Saturday to add to his 122 games for North Otago, as a blindside flanker. When he came on in the 70th minute he impressed with his cover defence.
North Otago was rewarded after a solid start with a Waenga penalty in the 12th minute.
At 24 minutes, the home team won a line-out and, after some good pick and go from the forwards, the ball was spun to the left where winger Lemi Masoe sent Waenga across with a perfectly timed pass.
The first five converted his own try.
Waenga added a penalty five minutes later to take North Otago out to a 13-0 lead before Quinlan kicked a 45m penalty into the breeze to put King Country on the board.
North Otago set up its next try from a line-out after a penalty 6m from the King Country line. From the ensuing maul, halfback Jason Forrest lunged over for a try, which Waenga converted.
Waenga then added a penalty two minutes from half-time to give his side a 23-3 lead at the break.
Early in the second spell, a Seduadua burst down the right touch led to North Otago being penalised.
The tap was taken quickly and Quinlan was driven over beside the posts for Murrell to convert.
Eight minutes later, a Waenga grubber kick inside the opposition 22 was gathered by Palenapa Mafi and Waenga went in for his second try.
The final quarter produced some King Country fireworks.
From a line-out Quinlan created space on the right and Seduadua galloped 40m to score, and Murrell converted.
Waenga kicked his fourth penalty to make it 31-17 but King Country roared back with tries to Seduadua in the 72nd and 75th minutes to narrow the gap to four points, but a desperate and tiring North Otago defence hung on.
- Terry O'Neill
