The two strikers have been linked with a host of top clubs over the past 18 months, including Manchester City, but neither man has come close to leaving the San Paolo.
De Laurentiis has admitted that he would be willing to negotiate with any interested parties, but reiterated that he has no intention of letting either Cavani or Lavezzi go on the cheap.
"Our players are not for sale," he told Sky Sports. "[But] if there are clubs interested they must make a proposal.
"To purchase our talents they need to put a lot of money on the table and then, and only then, will we speak about it.
"Everyone wants Cavani and everyone wants Lavezzi but at this moment nobody has ever made an offer."
Lavezzi and Cavani were both on top form as Napoli defeated Chelsea 3-1 in the first leg of their Champions League last 16 tie at the San Paolo three weeks ago.
De Laurentiis is hoping for a repeat of that performance in the return fixture at Stamford Bridge, but made clear that he is taking nothing for granted.
"It will be difficult against Chelsea," he warned. "We are hoping to close the qualification argument, but for us it is already a very important result to have arrived at this game."
Napoli's clash with Chelsea gets underway at 20:45CET on Wednesday night.
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