United have been heavily linked with the Uruguayan, thought to be frustrated at playing a supporting role to Zlatan Ibrahimovic for Paris Saint Germain.
French newspaper Le Parisien alleged on Monday that Cavani does not intend to stay in Paris beyond the summer unless circumstances change.
But Al-Khelaifi has now told the same newspaper: “I have not held talks with Cavani over his future. He is a young player and is the future of PSG.
“A ???50m (??35m) offer from Manchester United? I would not even look at such a bid.
“Edinson needs a bit more confidence, but his last game against Lille – in which he scored twice – was further proof of his talent.”
Cavani played as a striker against Lille in the absence of Ibrahimovic and scored his tenth and 11th league goals of the season.