Reports in the Italian media have suggested that Inter want to sign the player this summer, but Sao Paulo's vice president Joao Paulo de Jesus Lopes has said that they will reject any move.
"Inter Milan have not made any official offer and even if they do, we won't accept," Lopes told Globo Esporte.
"We don't have any intention of letting Wellington go, he is a very promising player and we all like him a lot at Sao Paulo.
"He has gained recognition, he is always paid when it's due and we are calm regarding Wellington."
The 22-year-old made his Sao Paulo debut in 2008.