Azzurri goalkeeper Matteo Gianello confessed to attempting to fix a game between the Azzurri and Sampdoria in 2010, bringing a hefty punishment on his former employers this morning.
Club captain Paolo Cannavaro and fellow defender Gianluca Grava were given six-month bans for failing to report their knowledge of Gianello's actions.
Napoli - and the two players - deny any wrongdoing and the club has also complained about the timing of the punishment, which they are expected to appeal through the FIGC's justice court.
A statement on sscnapoli.it read: "The president Aurelio de Laurentiis, the head coach Walter Mazzarri and the whole team are calm, being confident that no violation could be attributed to Napoli.
"While not entering into the obsolete and outdated principle of objective responsibility, and reserving any comments on legal action for the appropriate forums, Napoli does not agree with the decisions of the National Disciplinary Committee, considering that they should not be able to irretrievably alter championships that are already in progress.
"Any decision must be made before the start of a tournament or at the end of it. There has been enough time to evaluate and make a decision since the 2009-10 season.
"We are confident that true justice can be applied to the separate decisions, based on law and equity, not on Justicialism (a theory of government involving government intervention)."
The separate punishments come as a serious blow to Napoli's ambitions of catching Serie A leaders Juventus.
An indifferent run of form saw Mazzarri's men slip to third place and eight points behind Juve, with the deduction dropping the club to fifth place behind Inter Milan, Lazio and Fiorentina.
Gianello, now a free agent, has been suspended from football for 39 months for his role in what has been called the 'Calcioscommesse' scandal.
Napoli, Cannavaro and Grava are likely to appeal the hefty sanctions through the FIGC before approaching the TNAS tribunal court in Rome should they be unsuccessful.