Ho Quang Cua said that ever since his ST25 rice won first place at the 11th annual World's Best Rice Contest earlier this month, demand has skyrocketed.

"Before winning this award, my business supplied about a ton each month to an establishment in Ho Chi Minh City for VND20,000 ($0.89) per kilogram. But the ST25 rice is nearly out of stock," Cua said, adding that so far he has only opened one warehouse of rice reserves to sell to close friends and old business partners.

"The first few tons of rice have been sold out by the family's Ho Quang Tri private company for VND22,000 ($0.99) per kilogram."

In the Mekong Delta's Soc Trang Province, where the ST25 rice is cultivated, it is a hotly sought-after product by rice traders for sending to their secondary agencies or for retail, with an average market price of VND28,000 ($1.26) per kilogram. The price can go up to VND35,000 ($1.5) per kilogram in the neighboring city of Can Tho and in HCMC.

"In the past few days, my husband and I had to go through many suppliers to buy the ST25 rice, but we could get very little," said Trinh Thi Linca, owner of a rice shop in Soc Trang Town's Nguyen Thi Minh Khai Street.

Cua said the lack of supply has happened because his research team had only run a trial production so far. The rice variety is yet to be recognized by the Ministry of Agriculture and Rural Development, so the amount of rice produced was small, he added.

To protect the ST25 rice brand, Cua has requested that the ministry give this variety special recognition and add it to the national list of fragrant rice. He has also asked for funding to protect the ST25 brand worldwide and to increase production to meet the market's demand. His company is also redesigning the product's packaging with an internationally recognized logo to prevent counterfeiting, he said.

Cua also suggested that Vietnam should learn from Thailand and establish a national seed reserve so that there is enough supply should a product's demand increase suddenly.

Despite Cua saying the rice variety was almost out of stock, VnExpress found many shops in HCMC putting the "ST25" tag on their products.

At a rice shop on Le Duc Tho Street in Go Vap District, while no ST25 rice was displayed, the owner asserted that it is in stock. However, the shop’s ST25 rice was sold in 50-kilogram bags with no label, product name or place of origin, instead of the 5-10 kilogram bags that the genuine ST25 rice is sold in.

"The reason the rice is not packed into small bags like normal is because there are many retail customers buying only 1-2 kilograms. Furthermore, rice taken from merchants are usually sold in hundreds of kilograms or tons, we rarely buy packaged products," said Hoang, the shop's owner, adding that the rice variety was very popular and he sold several hundred kilograms a month.

When asked why the rice was labeled as "Sua Thai" instead of "ST25," Hoang claimed that it was to make it easier to read, and that he would provide more information should customers inquire about the ST25 rice.

Another shop on Pham Van Dong Street in Thu Duc District was also found using the "ST25" tag on rice products of unknown origin. According to its owner, this labeling was done by the merchants and he in fact had no knowledge of the product's origin.

The only thing he knew was that the rice was from the Mekong Delta, was of high quality and first-time buyers often come back for more, so he often buys around 500 kilograms each time.

Besides shops, ST25-branded rice could also be found sold on  social networks, with many sellers claiming they could sell 500 kilograms to 5 tons each time at prices of VND25,000-27,000 ($1.1-1.2) per kilogram, and some could even offer nationwide delivery.

Ngan, one such online seller, claimed that she had received orders for up to a ton of rice and advertised that her rice was bought directly from Cua. The rice delivered by her shop however was packed in 10-kilogram bags with no label.

Similarly, most of the hundreds of online shops that sell this product use images of Cua and the genuine product, with a wide range of prices that could go up to VND45,000 per kilogram. Despite the high prices, the products they deliver are usually packed in bags with no information about its origin.

The World's Best Rice Contest is an annual contest organized by The Rice Trader publication released as part of the World Rice Conference. At this year's contest, which was held November 10-13 in Manila, the Philippines, Vietnam's ST25 rice was named the winner, marking the first time a Vietnamese rice variety has won this contest in its 11-year history.