The speaker on the tape, purported to be bin Laden, the al-Qaeda leader, said he had personally assigned tasks to the 19 hijackers who staged the attacks on US cities which killed nearly 3,000 people.
"The truth is that he (Moussaoui) has no connection whatsoever with the events of September 11. I am certain of what I say because I was responsible for entrusting the 19 brothers ... with the raids," said the voice on the tape.
He said out of hundreds of people held on suspicion of links to the attacks, only two captives were connected to the attacks, but he did not name them.
"I call to memory my brothers the prisoners in Guantanamo, may Allah free them all, and I state a fact, about which I am also certain: All the prisoners of Guantanamo, who were captured in 2001 and the first half of 2002 ... had no connection whatsoever to the events of September 11."
The US administration was holding the detainees to justify the hefty costs of its "war on terror", the tape said.
No al-Qaeda connection
Bin Laden cited two Aljazeera employees - Taysir Alluni and Sami al-Hajj - as examples of the many who "have no connection with al-Qaeda".
Syrian-born correspondent Alluni was convicted by a Spanish court for conspiring with al-Qaeda and Sudanese cameraman al-Hajj is held in Guantanamo with no known charge.
The authenticity of the tape, which was posted on a website often used by al-Qaeda - could not be immediately verified.
Moussaoui was sentenced on May 4 to life in prison with no chance of release, ending four and a half years of legal wrangling over his fate.
The 37-year-old French citizen of Moroccan descent pleaded guilty to conspiracy in connection with the attacks, in which hijacked airliners were flown into buildings in New York City and Washington DC.