SAO PAULO, June 26 (Reuters) - Brazil is set to become the world's largest cotton exporter in 2023/24, knocking the United States from the top spot it has held for decades, following a more than 80% surge in shipments this season, local exporters' association Anea said.

With a month to go until the end of the 2023/24 cycle, the South American country's position as the world's No.1 exporter is a given, according to the group, driven by record output, strong demand from Asian countries and a drop in U.S. production due to adverse weather.

"It happened a little earlier than we imagined," Anea head Miguel Faus told Reuters. "The main reason is that there was a failure in the U.S. crop, while the Brazilian production increased."

Faus said Brazil's exports could increase further next season, as farmers begin to harvest a crop expected to hit a new record, and again in 2025/26.

"I think that in the medium term Brazil will consolidate itself in this leadership position", he said.

He cited data from the U.S. Department of Agriculture (USDA), which this month increased its forecast for Brazil's cotton exports this year by 300,000 bales to 12.4 million bales, while reducing the U.S. forecast by 500,000 bales to 11.8 million.

According to a USDA report seen by Reuters, the U.S. had led global cotton exports since the early 1990s.

Brazil already surpassed the U.S. in terms of production in 2023/24, ranking third in the world behind China and India - positions that are expected to be maintained in 2024/25.

Brazil has been more generally increasing its commodity exports, including of corn and coffee.

It has long been the world's largest coffee producer and exporter and Faus said it would still have more influence in that market than in cotton.

"In the case of cotton, the forces are more balanced... But of course, if Brazil's production rises or falls, the market will be paying attention," he said.

China, Vietnam, Bangladesh, Turkey and Pakistan are some of the largest buyers of Brazilian cotton. (Reporting by Roberto Samora; editing by Barbara Lewis)