The Old Golds fell away late in the second half to allow King Country to claim a come-from-behind win.
The game was marred by a plethora of yellow cards from referee Liam Scanlon which broke the rhythm of both sides, especially in the first half.
King Country built its pattern around a strong, cohesive forward pack that placed real pressure on North Otago, especially at the breakdown and set phase, and backed this up with a well-organised maul.
Captain Aarin Dunster led by example and was well supported by blindside flanker Anthony Wise and No 8 Rob Sherson.
King Country's tactics were marshalled expertly by classy halfback Zayn Tipping and first five-eighth Whakataki Cunningham, who drove the side intelligently around the paddock.
North Otago's tactical appreciation was under close scrutiny, especially in the first half, when hard-won ball was too often shovelled down the short side, a tactic easily nullified by the aggressive defence of the King Country pack.
The approach overlooked North Otago's strength out wide, where centre Lemi Masoe and wingers Simeli Koniferedi and Tenina Sauileoge looked able to breach the defence.
Young lock Jared Whitburn had a fine debut, Manu Taiti took good lineout ball and covered the country in the loose, and Sale Pi'i showed his power running with the ball in hand.
North Otago lost prop Djustice Duru-Sears with a serious leg injury but, on the whole, the front-rowers held their own, and newcomer Sione Teu made a positive impact in the second half.
With three losses from four games, North Otago faces missing the playoffs for the first time since the inception of the Heartland competition.
Coach Mike Mullins was adamant an inability to look after the ball and ill discipline were North Otago's main problems.
''This, and a couple or so yellow cards hindered us. When you're a man down, you can't play, and it makes it harder on the team that is still out there,'' he said.
''We changed tactics at halftime. The aim was to get us down the other end but we still played too much rugby at our end of the field.''
North Otago started well when Stephen Fenemor lofted a kick towards the corner and fullback Brad McKenzie, on debut, gathered on the full to score. Fifteen minutes into the half, the King Country forwards took play close to the North Otago line and Tipping slipped over between the posts.
North Otago continued to be indiscreet, and Cunningham slotted a penalty to give his side a 10-7 halftime lead.
Midway through the second half, North Otago began to move the ball wider and Pi'i broke to within 20m of the line. The support was forthcoming and Ralph Darling was awarded the try, which replacement first five Ben Palmer converted to give North Otago a 14-10 lead.
Five minutes from fulltime, from a lineout on halfway, King Country mauled North Otago back 45m, and second five-eighth Joe Perawiti scored a try and Cunningham sealed the win with a conversion.
Buller (18 points) surged to the top of the table in Westport when it beatSouth Canterbury 19-10. Horowhenua-Kapiti downed West Coast 19-17 to join South Canterbury on 15 points. Also on 15 is Poverty Bay, which defeated Wairarapa-Bush 23-10.
Thames Valley (14), which beat East Coast 20-8, is top of the provisional Lochore Cup standings, ahead of Mid Canterbury (13), which accounted for Wanganui 30-14.
King Country (10) and North Otago (7) are seventh and eighth. Wanganui (4), Wairarapa-Bush (2), West Coast (1) and East Coast (0) make up the bottom four.
By Terry O'Neill.
Heartland Championship
The scores
King Country 17
Zayn Tipping, Joe Perawiti tries; Whakataki Cunningham 2 con, pen
North Otago 14
Brad McKenzie, Ralph Darling tries; Stephen Fenemor con, Ben Palmer con
Halftime: King Country 10-7
