The Guardian reports that the Spanish side will make another bid after seeing their initial £14.6million offer rejected last week.
Agger’s agent Per Steffensen has revealed that the Denamark international could be open to the move.
He said: “We are aware that Barcelona have made an offer for Daniel that Liverpool have rejected.
“Daniel has a contract with Liverpool for the next three years and it would be up to the clubs to agree a fee for his transfer in order for that to change.”