The Uruguayan is strongly tipped to leave Naples over the coming months, with Real Madrid and Chelsea just two of the reportedly interested parties.
While Benitez insists that the club will not accept offers less than his £54m release clause, he concedes that there is nothing he can do should a potential suitor meet that figure.
"Neither me or the president want Cavani to leave because he's a really important player for us," Benitez told Radio Marca. "Clearly, there is a clause that you can't control, but we want him to stay to score many goals and to continue growing with Napoli.
"He found success and fame with this team and he can stay for another year with supporters who love him. Napoli don't need the money. Should he leave, it will be for his clause, and it's a really high sum.
"But our intention is that he will stay. The president's intention is to strengthen the team and Cavani is our most important player.I don't know if he has had any offers, but I know there is a clause and anyone who wants him will have to pay it."
Cavani netted 36 goals in 41 appearances for Napoli last season.