After suffering a horror string of injuries before the competition had begun, Wellington conceded two tries in the first half to trail Northland 15-nil at the break.
In the second half, the home side scored again before the visitors crossed for their only try of the match to fullback Jason Woodward, although the final pass looked forward.
Northland scored a fourth try in the 65th minute for a bonus point and a fifth from almost 100 metres on the stroke of full-time.
In the opening round, Wellington were beaten 37-25 at home by Waikato.
(Jone Macilai x2, Dan Pryor x2, Warren Dunn tries; Dan Hawkins 2 con , 2 pen)
(Jason Woodard try)