The match was marred by the sending off of East Coast captain Rua Tipoki midway through the first half.
North Otago coach Barry Matthews did not pull punches after the game, describing referee James Munro's performance as "shocking."
North Otago had the game all but sewn up after 10 minutes, racing out to a 21-0 lead.
Then came Tipoki's indiscretion and he was shown the red card for punching North Otago tighthead prop Palenapa Mafi during a confrontation following a scrum.
North Otago led by a hefty 40-10 at halftime but in the second spell the game deteriorated as a spectacle as referee Munro allowed the East Coast players free rein around the breakdowns as they attempted to slow down or kill possession for North Otago.
Matthews was left with mixed feelings.
"We played very well under duress. I think what was allowed to happen was shocking. The off-the-ball play went unnoticed by the referee and I thought our boys showed a lot of restraintin not lowering themselves to that level," he said.
"They played very well in the first half ... the scrum still struggled a bit but the lineouts were better and at the contact there was improvement. The refereeing in the first 20 minutes of the second half simply blew us off the paddock.
"I don't usually comment on the referees but I thought this afternoon he was shocking."
First five-eighth Ben Patston returned from injury to stamp his mark on the match, and he converted six of the eight tries.
Centre Lemi Masoe was quite outstanding, scoring two tries, while Taua Limuloa was master at lineout time. Willie Tahitua, getting a start on the openside flank, impressed with his pace and support play while hooker Will Hurst produced a fine 80-minute effort.
East Coast had a talented player in fullback Sikeli Vorenasu whose blistering pace saw him score a superb try after Tipoki's departure. Rocky Monika who came on at first five-eighth showed ability, while up front, Tom Kahukiwa who came on at tighthead prop, was a better-than-average scrummager.
North Otago was seven points up after just two minutes, when from a scrum near the East Coast line, halfback Hamish McKenzie drifted on the openside and blindside winger Whiria Meltzer came off his hip to score, for Patston to convert. Masoe then scored twice in quick succession, and East Coast looked lost.
But the visitor hit back with a mauling try to lock Ricky Waitoa but after a try by home No 8 Tevita Fifita, Tipoki was given his marching orders.
East Coast though did not immediately lose heart and Vorenasu flashed in for an unconverted try.
It was helter-skelter stuff with further tries in the first half to Christoph Bart, replacing Meltzer, and Faaitu Tuamoheloa.
Play deteriorated in the second half and the game lost structure.
Buller moved to the top of the Heartland Championship with 26-11 win over Wairarapa-Bush; Wanganui beat previously unbeaten Thames Valley 31-21; Poverty Bay beat Mid Canterbury 8-6 in Gisborne; South Canterbury scored six tries as it beat King Country in Taupo and West Coast recorded its first win of the season, beating Horowhenua-Kapiti 22-3.
The scores -
Heartland Championship
• North Otago 52
Lemi Masoe 2, Faaitu Tuamoheloa 2, Tevita Fifita 2, Whiria Meltzer, Christoph Bart tries; Ben Patston 6 con
• East Coast 17
Ricky Waitoa, Sikeli Vorenasu, Rocky Monika tries; Vorenasu con
• Halftime: North Otago 40-10.
