Nations they name as competitors include Fiji, Vanuatu and the Cook Islands.
Noni juice is said to benefit everything from the digestion to the immune system and even skin and hair.
Whatever the truth of that, in the past decade noni juice has become a multi-million dollar industry.
At the forefront of this success is the French Polynesian island of Tahiti, the first of the Pacific islands to tap into the international market.
But demand for Tahitian fruit is falling, and producers there suspect many companies may be using cheaper fruit imported from other Pacific growers.
They claiming noni from other countries is being used in juice carrying the Tahitian label.
High labor and production costs mean Tahitian juice is also far more expensive than that of its neighbors.
Vatea Quesnot, chief executive of noni producer and exporter Royal Tahiti Noni, told Radio Australia’s Pacific Beat program he saw substitution happen several years ago with juice sold in the United States, and thinks it may now be happening on the Asian market.
He said he suspects it is happening in Japan, because he believes Tahiti noni is not being sold there, despite claims on drink labels.
He concedes the higher labor and production costs in Tahiti, but says their produce is higher quality because of different soil conditions.
“I’m not saying the noni juice produced elsewhere is not good. Just that quality wise it is different,” he said
Quesnot is calling for controls in the countries where noni juice is sold. “For us, it is very difficult to compete.”
Morinda International, which provides raw materials for Tahitian Noni International in Utah, in the United States, has found itself at the centre of producers’ accusations.
But the company, French Polynesia’s largest exporter of noni products, says it has not been tempted to buy outside Tahiti.
Scott Tuitupu, Morinda’s manager of quality assurance, says the fall in demand for Tahitian noni is in line with market conditions affected by the global downturn.
The Pacific Island Noni Association promotes the benefits of noni fruit around the world.
Acting president Helen Russell said the debate over where the fruit originates is irrelevant.
Association tests show noni fruit has the same nutritional value regardless of its origin, she says.
But French Polynesian producers are lobbying their territory’s government to introduce a “guarantee of origin” campaign for Tahitian noni.
