"We're here...to show everyone that it is an unjust law and we need to change."
Media and bystanders nearly outnumbered the protesters at one point, with tourists showing more interest than former Deputy Prime Minister Sir Michael Cullen, who walked quickly into Parliament to shouts of, "Happy 420".
Mr Gregory's father, Andrew Gregory, made a speech in support of Kelly van Gaalen, who was recently jailed for two years after being found guilty of possession of cannabis for supply.
Van Gaalen, 38 and a mother of three, was a member of the Kaikohe-Hokianga Community Board as well as the chair of the Kaikohe Community Arts Council and promotions manager for the Kaikohe Business Association.
Earlier this month Judge John McDonald told the Kaikohe District Court that van Gaalen's husband had been the victim of a violent home invasion by three armed men on July 14 last year. Mr van Gaalen, who was home alone, managed to escape and raise the alarm.
However, when police arrived they discovered a bucket of dried cannabis and more in a snaplock bag. In total it weighed 684g.
Van Gaalen had told the court it was for personal use and to give away to about 20 close friends.
Judge McDonald said there was no evidence of commercial dealing, such as text messages on her phone, but Parliament had set the upper limit for personal use at 28g.
Van Gaalen had 24 times that and knew it was against the law.
"It is not for this court to comment whether that is a just law or not," he said.
Judge McDonald gave her credit for her previous good record and "extremely worthwhile contribution", but said he had to be consistent with sentences imposed for other, similar offences.
"To say this sentencing has troubled me is an understatement," he said.