A bitter-sweet stoush is brewing between a Government department and a drinks company part-owned by Olympian Hamish Carter.
The Ministry for Primary Industries says SOS hydration can't label its products as "electrolyte drinks" unless more sugar is added.
"We don't have enough sugar is our problem... we've been advised we must increase the amount of sugar to talk around dehydration," Tom Mayo, co-founder of SOS Hydration, told Newshub.
Sugar is one ingredient which helps the body absorb water faster.
Unlike other rapid rehydration drinks SOS contains contains just 2.5 teaspoons of sugar per litre, but food standard regulations state that in order to be labelled an electrolyte drink, it must contain at least 12.5 teaspoons per litre.
Sports doctor Sam Mayhew says New Zealand's rules are outdated and out of step with World Health Organisation standards - standards which SOS has met.
"To be told they need five times the amount of sugar content is concerning," he said.
He says that the amount of sugar required to give a drink an electrolyte label shouldn't be so high.
"Not in my mind no... it meets the standards and I think excess sugar is a big problem in the world and in NZ as well."
Despite that the Ministry for Primary Industries has given SOS an ultimatum for its sports drinks: change your labels or add more sugar.
"By the end of August we have to remove everything talking about rehydration, which is a shame really," Mr Mayo said.
MPI says the regulation is based on "the best available scientific evidence" and that SOS can self-substantiate its scientific claim, a process the company says would take time and cost upwards of $100,000.