The craze started in the UK early last year and in recent weeks has caught on in New Zealand, with a "Neknominations NZ" Facebook amassing almost 6000 "likes".
One video shows a young New Zealand girl, who appears to be in her late teens, struggling to down a 1-litre bottle of vodka in one attempt.
Alcohol Healthwatch director Rebecca Williams said the "worrying" game was promoting excessive and quick consumption of alcohol, which was made even more troubling due to the element of competition.
"It concerns me where will it go, in terms of people trying to out do the one before, and where does that kind of thing end?" Ms Williams said. "To me it could very well end in something quite tragic."
Another New Zealand example depicts a Kiwi wearing a reflective vest and holding a beer while sitting on a chair at what appears to be a building site. A colleague operating a digger lifts the bucket over the seated man's head and flicks the cap of the beer off, which the man then quickly drinks in one go.
"They're operating heavy equipment for heavens' sake," Ms Williams said. "There's an element of foolishness, dangerousness and really, really irresponsible behaviour."
Ms Williams said the game was made even more dangerous as it was being played on social media, where there were no age restrictions or limitations.
"There's no way to tell if these people are over the legal purchase age or not," she said. "So there's a real nasty dynamics going on around it."
