Three men have been arrested on suspicion of drug offenses following the death of a 25-year-old man near the Royal Welsh Exhibition Centre.
Police said he died despite the efforts of paramedics called to the camp at Penmenaw Farm at Llanelwedd in Powys on Saturday evening.
Interim head of support Steve Davis said it was a “tragic incident and our thoughts remain with the young man’s family at this difficult time.”
Wales’ largest annual agricultural festival, the Royal Welsh Show, is due to begin on Monday.
A spokesman for the Royal Agricultural Society of Wales said they would support police “as the investigation continues.”
“I would like to reassure the public that this is an isolated incident and the death is currently being treated as unexplained,” Davis said.
“There is no evidence of any ongoing risk to the general public in connection with this unfortunate incident.”
Three men remain in custody following their deaths.
A spokesman for the campsite said: “It is with sadness that we confirm that a person died yesterday following a medical emergency at the scene.
“The Penmenaw family would like to express our sincere condolences to the family, friends and loved ones of this man at this incredibly difficult time.”
Llyr Gruffydd, Minister for Agriculture and Sustainable Development, expressed his condolences to the man’s family and friends.
Speaking at a press conference on Sunday, he said: “It is important not to speculate on what happened and remember that police investigations are ongoing.”
“As a parent of children who will be on the show this week, it reminds us of the importance of thinking about others and looking out for each other,” he added.