Speculation surrounding the Croatian has been rife throughout the summer, with Chelsea being the favourites to land the 25-year-old.
While Redknapp is intent on keeping the playmaker, he said that he understands why he may be tempted by other clubs seeking his signature.
"I can understand how Luka feels in all this," said Redknapp. "If anyone offers to treble your wages you'd be interested and Chelsea are a big club.
"Everyone wants Luka. Just ask Alex Ferguson what he thinks of him, ask Roberto Mancini at Manchester City - they all want him. He could play for Barcelona.”
However, the manager suggested that Modric will be more inclined to stay at the club if it proves its ambition.
"Luka wants the chance to win things and he is ambitious. All I'll say is that we are too at Tottenham,” he added. "It's early days in the transfer market and no-one is more ambitious than our chairman Daniel Levy.
"Luka wants to know that we'll be right up there challenging next season and we are working hard to bring in a couple of big signings that may convince him to stick with us. I hope so."
Premier League rivals Manchester City and Manchester United are all reported to be keeping tabs on the midfielder.