Liverpool have issued a hands-off warning to Real Madrid after the Spanish champions declared an interest in the defender.
Real’s vice-president Jose Angel Sanchez has said the Danish international is top of the club’s transfer target list.
Liverpool signed Agger for £5.8m in the summer of 2006 from Danish side Brondby.
He quickly became a first-team regular and made 47 appearances in his first season at the club but has since fallen out of favour with Liverpool boss Rafael Benitez.
Agger played only seven times last season and has featured just twice this term, leading to speculation that he could leave the club.
Benitez, however, has said that Real would be wasting their time in making a bid for the Dane.
“The situation is very simple, Daniel Agger is our player and he is not for sale,” said Benitez on a statement issued on Liverpool’s official website.
“His future is at Anfield and nowhere else. He knows my ideas because we have talked with him and he has a long future with us.
“We do not want to lose our concentration just before we play Manchester City by talking about other things but it is important that people know that Agger is not for sale.”
Agger, who has two years left on his contract, reiterated his desire to stay at the club in a recent interview on Danish TV, but that has not stopped the Real vice president from declaring his interest in the player.
Sanchez told the Times: “We already had plans about buying Agger this summer, along with some other players, but the Robinho situation took so much attention and demanded so many resources from the club that we had to drop the plans about putting a bid in for Agger and other players that we had in mind.
“What we need is a defender and a striker, and, at the moment, Agger is on top of our list.”