The SITE monitoring service reported on Thursday that the audio by bin Laden, who was killed in a U.S. raid on May 2 in Pakistan, was included in an Internet video lasting more than 12 minutes.
Al Qaeda had said bin Laden, who masterminded the Sept. 11, 2001 attacks on the United States, recorded a message a week before his death.
In the audio, a voice which appears to be bin Laden's referred to the wave of revolutions which began in the Maghreb region of North Africa.
"The sun of the revolution has risen from the Maghreb. The light of the revolution came from Tunisia. It has given the nation tranquility and made the faces of the people happy."
Tunisia's president was overthrown in January, followed by Egyptian leader Hosni Mubarak after mass protests centred on Cairo's Tahrir Square.
"Tunisia was the first but swiftly the knights of Egypt have taken a spark from the free people of Tunisia to Tahrir Square," said bin Laden, adding: "It has made the rulers worried."
