The Catalans have already splashed £75m to land Luis Suarez from the Anfield club, and now they are plotting a move for his former defensive team-mate.
Barce are keen to bolster their backline after addressing forward-thinking concerns, and have been linked with Agger in the past.
With Liverpool set to announce Dejan Lovren’s signing soon, the Dane is likely to be surplus to requirements.
As a result, bids of around £12m are likely to be accepted for the Kop hero.
Agger has been a mainstay in Liverpool’s first-team since his 2006 arrival, but fitness concerns have been a persistent problem.
Barca see him as a good option to partner Gerard Pique at the back, with the Scandinavian having been praised for his technical abilities throughout his career.
Tottenham’s Jan Vertonghen is also an option for the Spaniards, but Spurs are said to be desperate to keep the Belgian.