Lazio president Claudio Lotito has warned potential suitors that Aleksandar Kolarov will not leave for less than 22.5million euros (£18.7m).
The left-back's future has been the subject of speculation for some time and Lotito announced earlier this week that the club would be prepared to let him go if their valuation of the player was met.
Lotito has now set the price, stating that Lazio want as much as they had to pay out to land Argentine striker Mauro Zarate.
Kolarov remains under contract at Lazio for 12 more months but his performances in Serie A over the past few years have attracted the attention of several top sides across the continent.
Manchester City manager Roberto Mancini has made no secret of his admiration for the Serbia international, who has been on World Cup duty this summer.
Real Madrid have also been heavily linked with Kolarov, although anyone hoping to secure his services will have to spend big money as Lazio stand firm.
"In my opinion, he is worth as much as Zarate, who we paid 22.5million euros for," said Lotito, who added that the player was not actively seeking a move away from Lazio.
"Kolarov has not asked to be transferred. He has only expressed an ambition to continue his career at a superior club.
"From our part, we have never put the player on the transfer market."