Lawyers for Italy's former premier Silvio Berlusconi threatened to walk out of his trial for alleged bribery after a court in Milan refused their bid to call dozens of extra witnesses.

Berlusconi's lawyers filed a number of motions on Saturday morning in his trial for having allegedly bribed lawyer David Mills to provide false testimony.

They applied to call around 60 witnesses and asked for the court to consider documents referring to people who had not been heard.

If permitted, it would have taken the case past the statute of limitations beyond which it cannot be tried.

When the court rejected their requests, his lawyers accused it of effectively declaring a premature guilty verdict on their client.

They even said they were consulting Berlusconi about walking out of the trial in protest.

"The problem isn't the prosecutor, it's the bench, which isn't impartial," said defence lawyer Niccolo Ghedini.

"In this trial only the prosecution witnesses have been heard," he added.

Prosecutor Fabio di Pasquale started his summing up, which he will continue at a hearing on Wednesday, during which lawyers for the defence are also expected to present their closing arguments.

In December, Mills testified by video-conference from London, saying Berlusconi was totally innocent.

Berlusconi is accused of having paid $600,000 (450,000 euros) to Mills, a British lawyer, in exchange for false testimony regarding other court cases dating back to the 1990s.

The court is expected to deliver its verdict on February 25.