Padelli has signed until the end of the season, but Liverpool have the option to sign him to a permanent deal.
Benitez said: “He’s a good young goalkeeper who has been selected for his national side.
“Padelli will give us a good option for the future. The fact he is once again with the under-21s for his national side tells you that we are signing a very good player.
“Our scouting department are working really hard to bring good young players to the club and I’m delighted we have been able to sign Padelli.”