The Italian prime minister is facing four concurrent trials, three for fraud or corruption and the sensational "Rubygate" case where he is charged with paying for sex with an underage Moroccan prostitute and then using his position to cover it up.
"We have presented a justice reform that is fundamental to us, in Italy we have almost a dictatorship of leftist judges," Berlusconi told a surprised-looking Obama during a pause in the G8 before world leaders began discussion of nuclear issues.
Obama got up from his seat and listened to Berlusconi's comments through an interpreter without making any reply.
In Italy Berlusconi constantly attacks Italy's judges and prosecutors, whom he accuse of persecuting him, but opposition leaders and the national magistrates association (ANM) were outraged that he should do so on an international stage.
"It's very serious that this has happened abroad and that a fundamental state institution should be denigrated even before one of the most powerful heads of state in the world," said ANM President Luca Palamara.