Inter Milan have been tracking Viduka and had representatives watching the Aussie striker play in Tuesday's goalless draw with Southampton.
Viduka has been lined up as an £8m replacement for Hernan Crespo at the Italian club, after the Argentine joined Chelsea this week.
Also Spurs are considering a bid for England goalkeeper Robinson who was a summer target for Aston Villa.
Leeds boss Reid is desperate for the international pair to stay and will hold talks with both of them aimed at seeking assurances about their future.
Reid wants to land Brazilian defender Roque Junior from AC Milan on a 12-month loan.
And the Leeds chief is hoping this will show Viduka and Robinson that the debt-ridden club are ambitious.
A Leeds source said: "Peter has made it clear how important both players are to Leeds.
"He doesn't want to see any more players leaving because he is trying to rebuild a side that can do well in the Premiership."
Reid knows other clubs are running out of time to swoop and is confident he can fend off interested parties.
The Whites opened talks with Junior after agreeing to pay his £40k-a-week wages and are confident of landing the Samba star.