Aurelio De Laurentiis says he will not accept any offers underneath his asking price for the Uruguayan, who is a target for Real Madrid and Manchester City
The Uruguay international has long been linked with a move away from the club, with Real Madrid and a host of Premier League clubs said to be interested in his services.
Cavani's influential performances for Napoli last season inspired the club to a second-placed finish in Serie A, while the 26-year-old finished as the highest scorer in the Italian top flight with 29 goals.
“Cavani has a contract for another four years and a buy-out clause worth €63m,” De Laurentiis wrote on Twitter in a question and answer session.
“We have received many offers for Cavani, but all of them were much lower than the buy-out clause."
Napoli recently appointed Rafa Benitez as successor to Walter Mazzarri, who joined Inter in a move which De Laurentiis described as “a wife who wants to sleep with someone else".
The Napoli president believes Benitez will show more loyalty and says his decision was based on the Spaniard's ability to win trophies.
“Many have asked me why I chose Benitez: because he won a great deal in his career and is a monogamous sort, seeing as he was at Liverpool for many years," De Laurentiis said.