The next stanza saw the hosts run in three unanswered tries with halfback Vern Wilson on target with the boot converting all tries and taking the tally 24-6 at the break.
The second 40 minutes proved tough for the visitors as fleet footwork found gaps and exposed the Bulls' ruck defence. Innovative running by centre Jordan Katene and standoff Junior Tatau produced a brace of tries for both.
Four tries were scored in 10 minutes in the second half at Fishburne Park to secure two wins from two to start their season off.
A consolation try off the back of the scrum from Robert Paniora gave their second half some credibility.
Despite the loss, new Bulls mentor and NZ Maori Coach Neville Rogers was upbeat.
"We're making progress but we are realistic about the time it will take to make changes to a team who has been together for a while," he said.
In other matches, Moerewa continued their good start to the season with a 44-10 win over Portland while Takahiwai made it a trio of undefeated teams after accounting for Hora Hora 58-6.
Otangarei 50 (Sam Henry 3, Jordan Katene 2, Junior Tatau 2, Frank Newton, Shaquille Ormsby, Shane Herbert-Porter tries, Vern Wilson 7 goals) beat Northern Wairoa 10 (Tamati Dick, Robert Paniora tries, Shelford Edwards goal)