The Blues have tabled a ?27million offer for the wantaway midfielder, but Tottenham are adamant that he will?depart for South Africa for the club's pre-season tour.
Blues Brothers: Modric in training at Spurs Lodge with Rafael van der Vaart
And Redknapp has hit out at Chelsea's bid for Modric, calling it 'way under' his valuation for the player.
The Tottenham manager said: 'We don't want to sell him. In my opinion, ?27million is a poor offer for a player of his ability. He's not for sale. There's nowhere to go with it.
'I would value him at way way way in excess of that. But even if they offered that, the chairman says he's not for sale.'
Spurs are deeply unhappy with their London rivals' pursuit of the former Dinamo Zagreb midfielder, who is 14months into a six-year contract.
Under orders: Harry Redknapp is determined to hold onto Modric this summer
Modric is eager to move to Stamford Bridge and launched a scathing attack on Tottenham chairman Daniel Levy at the weekend for blocking his dream switch.
Owner Roman Abramovich made another bid for Modric after Chelsea learned that midfielder Michael Essien would miss the next six months with a knee injury.
But Tottenham, already angered by Modric's verbal attack on Levy, are as determined as ever to resist their advances.
The Croatia international has stated in three interviews in recent few weeks that he is determined to leave White Hart Lane and complete a 'dream' move to Chelsea, who can offer him the Champions League football that Spurs can not.
Blow: Michael Essien (left) has been ruled out for up to six months with a knee injury
The latest interview he gave on Saturday with a Croatian newspaper has infuriated Spurs fans. The 25-year-old accused Levy of being 'arrogant' and of reneging on a deal that would allow him to leave Tottenham if a big club came in with a reasonable bid for the star.
Despite the stinging personal attack,Levy has not altered his stance with Modric and the club fully expect him to board the plane for South Africa when it leaves tomorrow afternoon.
The club are adamant that all their first-team squad will fly to the country, where they are scheduled to play in a tournament with Kaizer Chiefs and Orlando Pirates. Spurs' first match is on Saturday.
Modric's representative Nikki Arthur Vuksan confirmed the player will be going on the trip.
'Of course Luka will be going to South Africa. He is a Tottenham player and he has a contract there,' he said.
Sources close to Modric told Sportsmail the midfielder remains determined to quit White Hart Lane this summer, despite Tottenham's unwillingness to give in to his wishes.But handing in a transfer request was a last resort.
?Modric set to join Tottenham tour of South Africa despite demanding Chelsea switchChelsea test Spurs' resolve with ?27m bid for Modric after suffering Essien blowChelsea's title bid suffers early blow as Essien is ruled out for six months
Source: Daily Mail
Source: Daily Mail