The 25-year-old Croatia midfielder has made it clear he would like to move across London to Chelsea who, unlike Spurs, have qualified for next season's Champions League.
Tottenham rejected Chelsea's bid and Redknapp, speaking to Sky Sports, said on Monday: "I was surprised by the figure. It's a farcical bid.
"If they're going to make an offer, make an offer, but £22 million for Luka Modric is ridiculous."
But Redknapp would not say what kind of bid might interest Spurs, who reached the quarter-finals of last season's Champions League before losing to Spanish giants Real Madrid.
"We wouldn't put a valuation on him," he said. "He's such a fantastic player, we don't want to sell him.
"He's up there with the very, very best players in the Premier League and I think he can play in any team in the world, he's that good.
"But we don't want to lose him. We need to keep our best players, we need to improve our squad, not decimate it by selling our best players.
"There's no reason we can't show the ambition ourselves. I'm not saying we can pay the wages of Manchester City or Chelsea, but we've got a great group of players and if we can add a few more, anything could happen."
Meanwhile, Redknapp insisted Wales winger Gareth Bale, linked with a move to Italy's Inter Milan, would also be staying at White Hart Lane.
"Gareth will stay," he said. "He's a great kid, improving and learning the game all the time and he's coming on leaps and bounds since he broke into the team on a regular basis.
"He needs to stay at Tottenham and keep learning."
Source: AFP
Source: AFP