The Italian club are hoping to sell the center forward to raise funds in January, but will not agree to a cut price deal.
According to Goal, both Spurs and the current La Liga leaders Atleti have been told that it will take £13.5 million to sign Milik.
Another team that has an interest in the forward is Juventus.
Milik has 48 goals in 122 games for Napoli.
He stated in October that he wishes to leave the club, citing his own refusal to sign a new deal with the club in the summer.