The 26-year-old has been linked with a move to the Italian giants following a series of impressive displays in Serie A and the Champions League.
"It's fantasy football!" agent Alejandro Mazzoni told Radio CRC.
"This is an invention of journalists, because Inter have never contacted me and Napoli tell me that Inter have never asked Lavezzi.
"His contract expires in 2015. Speaking of an extension means speaking about the market and Lavezzi is not on the market."
Lavezzi joined Napoli from San Lorenzo in 2007.