White Hart Lane side aim to beat North London rivals to Belgian signing.
Tottenham have held initial talks with Ajax over a £10 million move for Jan Vertonghen after making him their top defensive target for the January transfer window, Goal.com understands.
Spurs manager Harry Redknapp is keen to bolster his defensive options and is looking for an upgrade on Sebastien Bassong, who is likely to be sold in the next transfer window.
Tottenham have been strongly linked with a fresh bid for Bolton defender Gary Cahill but Vertonghen has emerged as their leading target. The club have made their interest known to Ajax and believe the Amsterdam club would be willing to sell the 24 year old in the New Year.
Vertonghen, who has been closely tracked by Arsenal, is under contract at Ajax until 2013 and is widely expected to leave the Amsterdam Arena either in January or next summer.
Harry Redknapp has issues with a number of his current central defensive options, not least injury concerns over Ledley King, William Gallas and Michael Dawson, and a move for Ajax captain Jan Vertonghen makes a great deal of sense and a January bid may be more likely to succeed now that the Belgian international has seen his side crash out of the Champions League.
Tottenham have been on a fine run of form of late, notching up six straight Premier League victories but arguably they have not been so solid at the back. The White Hart Lane side has managed to keep just four clean sheets in domestic action and have conceded more goals than four of their top seven sides in the table.
Arsenal are also said to be tracking the 24 year old defender who can also work effectively as a defensive midfielder and has amassed a decent amount of top flight football and may well be interested in a new challenge after six seasons in the Amsterdam Arena first team.