The bill meant Mr Berlusconi would not have to sell a station

In an unusual move, Carlo Azeglio Ciampi asked parliament to re-examine the bill passed earlier this month.

Opponents have said it erodes freedom of the media, with the government saying it provides greater choice.

The bill reversed a court ruling which would have forced the PM's company to sell off one of its three TV stations.

The bill was passed on 3 December by the upper house of parliament after being approved in October by the lower house, or Chamber of Deputies.

Under Italian law, parliament can vote on the bill again without making any changes.

The president would be obliged to sign the bill if it passed a second time.

'Intelligent' changes

Mr Ciampi's move - the first time he has refused to sign a bill for anything other than budget reasons - came after he met Mr Berlusconi earlier in the day to discuss the matter.

After the talks, Mr Berlusconi said he was open to what he described as "intelligent" changes to the bill.

The bill contains a number of different provisions, including the creation of multi-channel digital broadcasting.

It also lifts the ban on cross-ownership of broadcast and print media in 2009 and increases the amount of advertising that one single company can have.

Crucially for Mr Berlusconi, the bill removes a previous restriction on one person owning more than two national broadcasting stations.

Mr Berlusconi is Italy's richest man, and as well as his three Mediaset channels - Italia 1, Rete 4 and Canale 5 - he holds political influence at the board of state broadcaster Rai.