France international Diarra has emerged as a key player for Pompey since arriving from Arsenal in January for £5m which has alerted Spurs.
But Fratton Park chief executive Peter Storrie has dismissed the links and warned the club's Premier League rivals not to waste their time with bids.
He told The News: "I had dinner with Daniel Levy from Spurs. If they were interested in Lassana Diarra I think he may have mentioned something!
"Being that I'm up at this meeting with Spurs I might have had an insight into that. Lassana is one of our most important players, and only arrived at the club in January.
"He is not for sale and that is the end of it."