Northland led 22-14 at halftime but found more resolute Auckland defence in the second half denied them the chance to score more points.
While Auckland's try in the opening seconds of the second half, to centre Sylvia Brunt, took a visit to the TMO to show the ball hadn't touched the dead ball line, they were within a knock-on of sharing the honours in the game.
Northland had conceded the first try of the game after 10 minutes when Auckland centre Theresa Fitzpatrick ran back on the angle to take the pass of first five-eighths Ruahei Demant to explode through a gap for a clear run to the line.
Almost from the restart, Demant ran a tap penalty and was on hand when wing Princess Elliot cut back inside to take the ball and corkscrew her way across the line.
But from the restart, Northland first five-eighths Victoria Subritzky-Nafatali stole the ball from the hands of Auckland halfback Moana Cook at the back of the ruck and ran 20m to pull the margin back.
Centre Portia Woodman then made a superb break to carry play back to the Auckland line and when Northland won a scrum out from the goal-line, Aroha Savage, playing at No 8, took the ball and fed halfback Tyla Nathan-Wong on the blindside and she found a gap and scored to claim the lead for Northland.
That was extended when prop Krystal Murray produced a lovely offload just out from Auckland's line that saw Savage cross.
While Brunt was able to take advantage of a Northland mistake, a passed ball glancing off a home player to allow a kick to the in-goal area, it was another 16 minutes before Auckland could ease ahead. That came after a turnover that gave Fitzpatrick space on the outside to score.
The final moments were anxious for Auckland after a series of tap penalties, one of which came after Nathan-Wong had been late-charged, resulting in Elliott being sin-binned, carried Northland to the line.
One bullocking run by Murray looked to have produced a chance to level the scores but a TMO check revealed a knock-on at the line and Auckland managed to scramble their way clear for the win.
In Sunday's second game, Otago faced a late challenge from Hawke's Bay who, after wing Kaitlin Bates landed her fifth penalty goal after 74 minutes, led 20-19.
But second five-eighths Kilisitina Moata'ane scored her second try of the afternoon from the restart and then a Hawke's Bay turnover in Otago territory saw first five-eighths Rosie Kelly take a lovely gap to run 60m past the defence to score the match-winner two minutes from the end.
Earlier, in the weekend Bay of Plenty rocked North Harbour with a 67-17 win in Albany while defending champions Canterbury were too strong in taking a 36-10 win over Manawatu.
Waikato thumped Taranaki 76-14 in Inglewood and Tasman went down 0-62 to Wellington.
North Harbour 17 (Zakiya Kereopa, Pia Tapsell tries Hayley Hutana 2 con, pen) Bay of Plenty 67 (Alena Saili, Kiani Tahere, Angel Mulu, Mahina Paul 4, Les Elder, Luka Connor, Karli Faneva, tries; Kelly Brazier 7 con, pen). HT: 3-38
Manawatu 10 (Selica Winiata, Janna Vaughan tries) Canterbury 36 (Pip Love, Alana Bremner 2, Grace Steinmetz, Cindy Nelles tries; Kendra Cocksedge 4 con, pen ). HT: 10-15
Waikato 76 (Stacey Fluhler, Cheyelle Robins-Reti 2, Grace Houpapa-Barrett 2, Tanya Kalounivale, Chelsea Alley 2, Toka Natua, Ariana Bayler, Merania Paraone tries; penalty try; Alley 6 con; Tenika Willison con) Taranaki 14 (Paige Neilson, Chloe Sampson tries; Gayle Broughton 2 con). HT: 38-14
Tasman 0 Wellington 62 (Monica Tagoai, Jackie Patea-Fereti, Dhys Faleafaga 3, Thamsyn Newton, Charlene Gubb, Joanah Ngan-Woo, Isadora Laupola, Nina Foaese tries; Newton 6 con). HT: 0-36
Northland 22 (Victoria Subritzky-Nafatali, Tyla Nathan Wong, Aroha Savage tries; Timara Leaf 2 con, pen) Auckland 29 (Theresa Fitzpatrick 2, Ruahei Demant, Sylvia Brunt tries; Patricia Maliepo 3 con, pen). HT: 22-14
Otago 29 (Kiana Wereta, Kilisitina Moata'ane 2, Teilah Ferguson, Rosie Kelly tries; Rosie Kelly 2 con) Hawke's Bay 20 (Kathleen Brown tries; Kaitlan Bates 5 pen). HT: 14-11