The Criminal Bar Association says lawyers will invoke a rarely-used legal procedure to try to bring the issue of prison overcrowding to a head.

A number of people in custody have been missing scheduled appearances in the Magistrates Court, while Corrections Victoria struggles to deal with the high number of prisoners in the system.

The chairman of the Criminal Bar Association, Remy Van de Weil, says it is a serious problem.

"We've got hundreds of people who have been in that position where they have not been brought to court," he said.

"They're innocent people. They're waiting to be dealt with in terms of a court hearing.

"We've got people, as many as three times, being failed to be delivered (to the court)."

Mr Van de Weil says lawyers may soon use habeas corpus, which would allow the Supreme Court to order the immediate appearance of a prisoner.

He says it as a power the Magistrates Court does not have.

"If that's done it means we can have a proper review of the system with a Supreme Court judge and hopefully that will bring some further expenditure and proper consideration of the problem," he said.

Attorney-General Robert Clark makes no apology for keeping dangerous offenders behind bars.

"Prison beds are being constructed as fast as they can," he said.

"If it's a choice between dangerous offenders on the streets and having them behind bars then this Government will keep them behind bars.

"There's certainly an issue with moving prisoners from cells to court and back again. All the authorities are working to manage that increase."

Mr Clark says other measures are also being taken to relieve the pressure in the system including having the Magistrates Court sitting on weekends.

Mr Van de Weil says the situation is so bad some people are being held in prison vans outside the court.

"If you go to Lonsdale Street now outside the Magistrates Court you will see a bank of prison vans there," he said.

"What's happened is the custody centre is full so they're using the prison vans as transfer points to try and get people in and out of the courtroom."

Mr Clark says he is not aware that that is the case.