The PM's office issued a statement on Monday that some broadcast media reports had been "conflicting, unreliable and dangerous for the safety of the hostages".
Three Italians working for a US security firm have been held in Iraq since they were kidnapped outside Baghdad last month.
A fourth Italian snatched with them was murdered after the captors demanded the withdrawal of Italy's 2700 troops in Iraq.
Some television programmes said they would not adhere to Berlusconi's request, some said they would, while others said they would be more cautious in their reporting on the situation.
Opposition politicians ridiculed Berlusconi's request, accusing him of making statements about the hostages they said were contradictory and counterproductive.
In recent weeks there have been various reports the Italian hostages would shortly be released, but they have turned out to be premature.
Government representatives in Iraq have been trying to win their freedom through intermediaries such as the Italian Red Cross.
Berlusconi's family controls the Mediaset network and its three channels.
Through his political office he has indirect control over state broadcaster RAI whose Porta a Porta chat show has run several shows on the crisis.