Acid-tongued Joan Rivers has hit out at the US justice system, slamming juries on high-profile celebrity cases as being comprised of "morons".

The notoriously outspoken comedienne cites the Michael Jackson case as a particularly good example of a jury behaving irresponsibly for acquitting the singer of child molestation charges in June (05).

She says, "How could the jury at the Michael Jackson trial have been a jury of his peers? They all had noses.

"Anyone in that jury had to be a moron. But it's nothing new in America.

"We've had three idiot juries - at the cases of OJ Simpson, Michael Jackson and Robert Blake.