An unnamed Australian legal firm is advertising in New Zealand for people who believe they have health problems caused by addiction to cola-based drinks.
The firm plans to look at a possible class action against international cola companies once it has spoken to such people.
The director of Just Water, Tony Falkenstein, is collecting the names of those interested in getting involved and then passing them on to Australian lawyers.
He says he has signed a confidentiality agreement with the firm, which does not expect to file court papers for at least six months.
Mr Falkenstein says a few people have been in touch with him, but he cannot give more information about the action.
A senior researcher into the effects of sugary drinks believes the proposed class action could lead to major changes within the soft drinks industry.
Gerhard Sundborn, from Auckland University's School of Population Health, says the action may extreme but the drinks industry needs this sort of encouragement to start making a product that does less harm to consumers.
"If you compare this to what happened with tobacco back in the 60s, you'd argue that those who proposed to bring about class actions with regards to tobacco they would have been considered kind of extremist then."
The New Zealand Juice and Beverage Association's executive director, Kerry Tyack, says members won't be taking the action seriously.
"It just seems to us to be something of a publicity stunt from a company selling an alternative product. Calories come from all sorts of sources - not just drinks - and it seems just baseless to be trying to target one source of that energy."
Mr Tyack believes this is one person's campaign against a particular company.