The Rebels Motorcycle Club has apologised for disrupting today's Dawn Service in Waiouru.
A written statement emailed late this afternoon said the club had the "upmost respect for our fallen heroes whom have given their lives for our freedom".
"We were passing through at the time of service; we stopped to pay our respects. Assuming the service was completed, we then continued on our journey. "Unfortunately, we misunderstood, causing disruption, this was not our intention. There are no excuses for the events that occurred; we can ensure you this will not happen again in the future.
"We deeply apologise for this, all hope that this apology is accepted."
A grandmother who was at the service said members of the gang turned up to the service in the central North Island and revved their motorbikes while a bugler payed the Last Post.
Merna Brotherston, who was at the service with her daughter and two grandsons, said the disruption was "despicable" and shocked hundreds of people paying their respects.
"It was really disgusting because there were lots of families there, people turned out with babies in prams and everything. The din was horrendous, then they drove off and it was just despicable -- what a lack of respect."
Her daughter Andi Brotherston tweeted photos showing patched gang members at the service, and said: "Perhaps the most disrespectful moment in the history of #AnzacDay."
She also captured the incident on video.