New Zealand border authorities were warning Pacific island visitors that their "miracle water" could be costly if they bring it into the country.
The Ministry for Primary Industries (MPI) said its border staff had seized miracle water from almost 500 air passengers arriving from Fiji since November.
Sourced from a natural spring in Dawasumu, the untreated water was claimed to have healing properties that could cure anything from conjunctivitis to blindness.
"Our concern isn't whether the healing properties are real or not, but whether it contains waterborne diseases that could harm New Zealand's freshwater aquaculture and natural environment," MPI manager north passenger and mail Craig Hughes said on Monday.
"The locals may call it miracle water, but it is untreated, so it poses a biosecurity risk to New Zealand."
All arriving passengers were required to declare the water at the border.
"If they want to keep it, they have to pay for heat treatment, which costs around 60 NZ dollars (42 US dollars). If they don't declare it, they face a 400-NZ-dollar (282 US dollars) fine or prosecution," said Hughes.
MPI was running a campaign to inform travelers from Fiji about New Zealand's biosecurity rules regarding untreated water, which included notices at Fiji's Nadi Airport.