Magistrates in Italy are beginning a three-day strike against reforms.
Berlusconi and the magistrates have clashed repeatedly
They say the government proposals undermine their independence and career prospects - and do little to speed up the notoriously-slow judicial system.
But the government says the measures - which would make magistrates choose to be either prosecutors or judges - would make justice fairer and swifter.
PM Silvio Berlusconi has often accused the judiciary of being left-wing and of plotting to force him from office.
The strike is something of a show of force by Italy's magistrates in the face of reforms they say will undermine their autonomy and give the executive excessive control.
They say the package of measures is in contrast to the constitution and does little to tackle the real issue, the snail's pace of Italian justice.
There are huge backlogs in most courts and an average trial takes at least a couple of years to reach a first verdict before any appeals.
The government maintains that splitting the magistrates clearly into judging or investigative bodies is vital for a fair trial.
It also argues that the prosecutors currently have too much power - and at times abuse it.
The judiciary and the government have been at loggerheads for three years now.
The overheated climate is not helped by the fact that Mr Berlusconi, who was on trial in Milan for alleged corruption, has publicly accused some magistrates of trying to oust him by a political use of judicial probes.
He has also passed a law allowing trials to be shifted if there is a legitimate suspicion of court bias, as well as a bill giving himself immunity from prosecution - which was later thrown out by the constitutional court.