Mr Andreotti was prime minister seven times in the post-war period

The Court of Cassation's ruling was the third and final judgement in the case.

He was cleared in 1999 and 2003 of having protected the crime group while he was in power.

Mr Andreotti, 85, who served as prime minister seven times and is now a life senator, has always claimed he was the victim of a Mafia vendetta.

But the ruling on Friday supported the opinion of judges in the 2003 appeal that made a clear distinction between events before and after 1980.

They said they believed Mr Andreotti did have friendly ties with the Mafia before 1980, but could find no evidence of links after that time. They said the law could not deal with possible offences before 1980.

Mr Andreotti had appealed for a ruling of full innocence.

Last year, Italy's highest court acquitted Mr Andreotti of charges he ordered the Mafia killing of a journalist in 1979, in a separate Mafia-related case.