The team had five wins and two losses during the week, showing that Otago women's golf has made vast strides over the last two years.
From 2005 to 2008 Otago was placed last each year, while this year's fifth is two places better than the 2009 result.
The final win was not without some stress, as the middle order were all trailing with four holes to play.
Lisa Henderson (No 2) fought back to halve with Saini Skudder while Laura Hoskin (No 4) won three of the last four holes.
Monica Tulisi led the way at No 1, beating Heather Lavery by 4 and 2 to give her six wins from seven matches.
Tulisi's performance now puts her up with the best in New Zealand and she could be on the brink of national honours.
It was a solid team effort with Henderson posting four wins and two halves, Shani Arona (No 3) winning four matches and Hoskin posting three wins and a half, while on debut, Jo Hicks-Beach won three games.
Hicks-Beach was always in front in her final match against Rotana Howard and was three up with three to play.
But she lost the 16th and 17th holes and had to par the final hole to what ensure a crucial win.
North Harbour sealed a faultless week to win the championship, making amends for a harrowing extra-hole loss to Auckland in last year's final by beating Waikato 3-1 in Saturday's final.
Harbour was led superbly by 13-year-old Lydia Ko, who was awarded the player of the tournament with eight consecutive wins, all under par.
Ko sealed the title for her team when she slotted a 7m birdie putt at the 16th hole against Emily Perry, whose birdie putt to keep the rubber alive lipped out.
Ko said she had memories from last year when she came to the 16th in the pivotal clash to decide the interprovincial title.
"They told me that I needed to get at least a half for us to win. I thought back to last year when it was the same and I didn't win," Ko said.
"Then Emily hit that great shot in and I got nervous. But I blanked it out and just concentrated on my putt, and had some confident thoughts and it went in. I am just so happy for me and for my team.
"I was really happy with how I played this week and all the team contributed."
It was North Harbour's fifth win in the tournament and its fourth title in the past 10 years.
It started the final strongly to be up in four matches after six holes before Waikato fought back and by mid-round the clash was even.
Waikato No 5 Hanna Seifert secured her eighth straight win, getting home 3 and 2 over Kristin Farrell, while Harbour scored victories to captain Rebekah Brownlee (5 and 4) and No 2 Rica Tse (3 and 2).
The clash between the No 4s was a rollercoaster ride, with Faye Amy Nickson two-up early for North Harbour before unbeaten Charlotte Willson fought back to take a three-up advantage. The North Harbour player dug deep to go one-up at the 17th before Willson evened things with a brilliant birdie on the final hole.
That left the attention firmly on the Ko-Perry battle, which the remarkable 13-year-old settled with a 2 and 1 victory and her eighth straight score in the 60s to complete a superb week.
Earlier, Waikato disposed of defending champion Auckland 4-1 in a strong semifinal display and Harbour cruised into the final with a 4-1 win over Wellington .
- Additional reporting by NZPA.
