Tottenham manager Harry Redknapp insists a bid of £35m would not meet his valuation of wantaway midfielder Luka Modric.
The Croatia international has been the subject of two unsuccessful bids from Chelsea this summer but is reportedly determined to quit White Hart Lane.
A figure of £35million has been mentioned as one which would tempt Spurs into selling but Redknapp is eager to hold out for more.
"If we were looking to sell him it wouldn't meet my valuation," he said. "I think he is worth an awful lot more money than that.
"Really we're not looking to sell Luka. We need to keep our best players so he is a player that we want to keep if possible.
"It is in the hands of the chairman of the football club [Daniel Levy]. It's not my decision at the end of the day.
"I obviously want to keep him as the coach but the chairman says he is not for sale so we'll have to wait and see.
"We're quite determined, if we can, to hang onto him but it is a difficult situation.
"It's a difficult one for Luka and it's a difficult one for Tottenham."
Tottenham face Orlando Pirates tomorrow in the Vodacom Challenge final at Ellis Park.
Spurs have taken on Kaizer Chiefs and the Pirates on their South African tour so far and Redknapp has been pleased with his side's exertions.
He said: "The preparations have been fantastic and we have had some tough games here.
"I have been very impressed and the football has been of the highest standard."
The former Portsmouth boss has promised to play Bafana Bafana midfielder Steven Pienaar in the tournament finale after he missed the previous two matches with a knee injury.
"I'm happy that Steven is training and looking to give him a start against the Pirates," he said.
"I'm hoping that he gets at least gets 45 minutes of action.
"It's his home country and he has been looking forward to playing."Reuse content