Spurs have won just one of their last nine Premier League games and have consequently dropped into fifth place in the Premier League table. However, Redknapp does not expect the key duo to be sold at the end of the season.
"No, I don't. When they came to the club, Tottenham weren't in the Champions League, and were nowhere near getting in the Champions League," Redknapp told Sky Sports News.
"They play for Tottenham. They're at a great club. There's no reason they should want to leave. If we don't make it this year we'll try again next year. There's not too many clubs they could go to better than Tottenham.
"Gareth Bale and Luka Modric have both signed long-term contracts. Gareth has had a fantastic time for young player at Tottenham. He needs to stay at Tottenham a few more years yet and keep developing."
Tottenham face Blackburn Rovers in the league on Sunday.