The 10-minute debate focused on "reconnecting" youth with their society and whether the policy would give teens work and volunteering experience.
MP Tracey Martin was among those who spoke in favour.
"To build up that sense of community among young people, let's try to find a system that we can compulsorily require young people to volunteer in their community," she said.
"I suggest we do that with a carrot, rather than a stick."
There was grizzling in the room after a vote on the issue was called and passed without anyone being given a chance to speak against it.
Other proposals included supporting an independent review of the Auckland Super City and trialling methane-reduction technology including GMO rye-grass.
The party's members voted down proposals to make vaccinations compulsory for school children and increasing the drinking age off-licence to 20.