"Hassan is not for sale, he is staying with us until the end of his contract next season," he said in a press conference after Anderlecht ensured they will be playing in the UEFA Champions League next season.
The former Besiktas man said earlier he will return to Egypt for family reasons but it remains to be seen whether he will be able to do so following the chairman's statement.
Van Den Stock revealed a Qatari offer for Hassan worth $1.5M, but said that the bid has been officially turned down.
"We rejected a $1.5M from a Qatari club for Hassan, but the offer was totally unacceptable, his price is much higher than that and we are not willing to sell him."
"We wouldn't even sell him for four or five million euros."
Egypt captain Hassan has been in superb form in his first season with the Belgian champions, as he scored 15 goals and produced some consistent performances to help the Purple and White win the Belgian league and Super Cup.