One of the "wise men" charged with finding a way out of Italy's political crisis apologised today after he made offensive remarks about centre-right leader Silvio Berlusconi during a prank phone call organised by a radio show.

Valerio Onida, one of the 10 experts in institutional and economic affairs set up by President Giorgio Napolitano, said Berlusconi was looking for protection from his legal problems and it would be better for Italians if he quit politics.

Telephoned by an impersonator from Radio 24 pretending to be well-known Italian scientist Margherita Hack, Onida also said that Napolitano's initiative was "probably useless" and was merely intended to play for time.

"Berlusconi is old, let's hope he decides to enjoy his old age and leave the Italians in peace," said Onida, a former president of Italy's constitutional court.

"Berlusconi of course always hopes to get some advantage or protection," Onida said, as the fake scientist prompted him for his views on the political gridlock in place since the February election.

The president's palace later issued a statement in which Onida apologised to Berlusconi and said he regretted the embarrassment that the episode might have caused to Napolitano.

Napolitano's decision on Sunday to appoint the two working groups was heavily criticised as no more than a delaying tactic after he was unable to broker any deal among the parties to form a government.

Onida, considered close to the centre-left Democratic party, already raised eyebrows when he admitted soon after his appointment that he was "not too optimistic" about finding a consensus.

The election resulted in three main blocs, none of which has enough support in parliament to govern alone. The centre-left holds a majority in the lower house, but not in the Senate.