Spurs are desperate to reinforce their defence having missed out on Gary Cahill in the summer and once again seen Ledley King's campaign disrupted by injury.
Montoya and Bartra have made just five appearances between them at the Nou Camp despite being two of La Masia's brightest prospects.
Hot Spurs: Tottenham are tracking Marc Bartra (left) and Martin Montoya (right)
And with their path to the first team blocked for the forseeable future, they could force a move in January with the prospect of them leaving for nothing next summer.
Radio station talkSport claim Tottenham, who have offered better terms than the duo's current club, lead the chase, although a number of more prestigious European clubs have also shown an interest.
On the defensive: Harry Redknapp is short of options at the back
Tottenham have enjoyed a solid start to the new Premier League season, but have managed just two clean sheets using several different combinations in the heart of their defence.
As well as King's on-going problems, Spurs are also without Michael Dawson [achilles] and William Gallas [calf] for an extend period, leaving Harry Redknapp no choice but to field Younes Kaboul and Sebastien Bassong for their Europa League home game against Rubin Kazan on Thursday and at Blackburn in the league on Sunday.
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