Napoli president Aurelio de Laurentiis has fired a major warning to his underperforming players.

Gazzetta dello Sport says De Laurentiis delivered his fiery message to the players at the club's Christmas dinner.

"Until now, you have been disunited on the field and united only outside of it," said the movie mogul.

"You are now under my magnifying glass, I will not excuse anyone. I expect great things from you, you have to prove to be champions.

"Until now we joked, now the concentration must always be highest. Between me and you there is a pact of honor!"