Duffy is one of the players instrumental to the change of fortunes at the Vetch Field as Swansea have gone from relegation candidiates to promotion contenders in the space of one season.
But Swansea City chairman Huw Jenkins told the South Wales Evening Post:As far as I know nobody from Portsmouth has been in touch with us and we're not looking into their interest.
"People like Richard Duffy and Lee Trundle are the ones we want to keep at this club to help us move forward."
Portsmouth are planning to line up a 500k bid for Duffy next month; but even if Duffy rejects the contract extention, Swansea will be entitled to a fee as the player is under 24 years old.