Despite their 10-point deficit at the halftime break, Harbour were almost the equal of Otago in an entertaining opening spell. Territory and possession were split down the middle and only a lack of discipline, which handed the visitors more chances than they deserved, saw Harbour fall behind.
Lapses of concentration were also an issue, and one in the opening moments saw Jayden Spence stretch out to score the game's opening try under the posts. Fumiaki Tanaka exploited another hole in the Harbour defence just before the break, allowing Tony Ensor to cross in his first game back after dislocating a shoulder.
But just when Otago looked set to take a commanding lead to halftime, Francis Saili showed his undoubted power to bump off Hayden Parker and go under the posts.
It was a stop-start opening to the second spell, with scrum resets and penalties preventing the flow that was present in the first half. One such infringement soon saw Harbour pull within seven, with the home side stringing together numerous phases until Otago's defence was left to pay the penalty.
But Otago then found a reward of their own for a concerted period of possession, doubling their lead when Sam Anderson-Heather crashed his way over in the corner following a steady build-up near the Harbour line.
And Gareth Evans soon sealed victory and snatched what could prove to be a vital bonus point, receiving an inside pass from Aki Seiuli after TJ Ioane spied some space out wide.
With a spring in Otago's step, Harbour were in danger of receiving a second straight thrashing, but Brenton Helleur scored a late consolation to add some respectability to proceedings.
North Harbour 23 (Saili, Helleur tries; Elrick 3 pens, 2 cons)
Otago 37 (Spence, Ensor, Anderson-Heather, Evans tries; Parker 3 pens, 3 cons, Breen con)
HT: 13-23
