Arsene Wenger is trying to bring Gonzalo Higuain to Arsenal and his first bid of €40m (£29.4m) has been turned down.
The Frenchman is a keen admirer of the Argentine striker and previously tried to buy him from Real Madrid in 2013.
According to Gazetta dello Sports, Napoli – missed out on Champions League qualification on the final day of the season and are holding out €50m (£36.7m).
Wenger, who won the FA Cup for the second successive year, is seeking to bolster his squad ahead of next season’s challenge for the Premier League title.