The Roos, who remain out of the top eight on percentage, led at every change to win their seventh game of the season, 19.15 (129) to 14.9 (93).
The roof was shut on a wet and cold Melbourne afternoon, yet just 15,109 people turned up, although those who did saw an encouraging performance from the home side.
With the Port Adelaide defence weakened by the late withdrawal of Troy Chaplin, Lachlan Hansen dominated an out-of-sorts Chad Cornes early in the game, before also proving too good for Alipate Carlisle. He finished the day with five goals.
Cornes finished the game with 21 disposals, but had little impact on the contest.
In contrast, Jay Schulz bagged a career-best haul by kicking seven of Port Adelaide’s 14 goals.
Down by 28 points at the final change, the Power briefly fought back early in the final stanza, when Daniel Motlop finally came to life with two goals, before Brad Scott’s men pulled away again to enjoy a comfortable win.
Thanks to the split round, both North Melbourne and Port Adelaide have next weekend off.
The Power, who have slumped to 5-8, travel to Perth to meet Fremantle at Subiaco Oval in their next game.
North Melbourne 4.2 6.7 13.12 19.15 (129)
Port Adelaide 3.3 4.6 9.7 14.9 (93)
GOALS
North Melbourne: Hansen 5, Harvey 2, Campbell 2, McIntosh 2, Warren 2, Swallow, Thomas, Bastinac, Garlett, Goldstein, Wright
Port Adelaide: Schulz 7, Hitchcock 3, Motlop 2, Meyer, Rodan
BEST
North Melbourne: Harvey, Hansen, Swallow, Garlett, Greenwood, Pratt
Port Adelaide: Schulz, Cassisi, Pearce, Stewart, Rodan
INJURIES
North Melbourne: Cunnington (broken nose)
Port Adelaide: Stewart (broken nose)
Reports: Nil
Umpires: McLaren, Kamolins, Pannell
Official crowd: 15,109 at Etihad Stadium
