The Victorian Government will introduce a new law into Parliament to keep mass murderer Julian Knight behind bars indefinitely.

The Hoddle Street killer is eligible for parole in May after serving a minimum 27-year sentence.

Knight, a former army cadet, was sentenced to life imprisonment for killing seven people and injuring 19 others in what became known as the Hoddle St massacre on August 9, 1987.

Victorian Premier Denis Napthine says legislation specifically targeting Knight will be introduced into Parliament today.

The Premier says that means Knight will only be released if he is in imminent danger of dying or is seriously incapacitated.

"This is a special situation for Julian Knight," he said.

"Julian Knight is our worst mass murderer.

"(He was) convicted of seven murders and has a history of further inappropriate behaviour and disrespect for our fellow man whilst in jail.

"He deserves to rot in jail."

Dr Napthine believes the legislation will be supported by all Members of Parliament, the victims and their families and especially members of the emergency services.

"I think all Victorians but particularly those who are families of victims, particularly those who are in the emergency services and those who are directly affected by the Hoddle St massacre... will applaud and support this legislation because they know Julian Knight is our worst mass murderer," he said.

"He has shown no remorse, no regret and has showed no evidence of changed behaviour."

The Government had to table special legislation in 2011 to prevent Knight from writing to his victims.

He has also sought access to his prison records to see if allegations against him in prison would affect his chances of parole.

Knight has made so many complaints about his treatment in prison that the Supreme Court declared him to be a vexatious litigant.

He now requires court approval before launching any legal action.

New law branded unfair

Greg Barns from the Australian Lawyers Alliance says he has numerous concerns about the plan.

"Julian Knight, whatever you think of him, has certain rights," he said.

"When he was sentenced to life with 27 years, to then retrospectively say no, that's not your right, that is grossly unfair.

"It also means that it sets a very dangerous precedent for governments to think they can make policy on the run to undermine peoples' rights."

Jeff Lapidos is a former prisoner advocate and he remains in regular contact with Julian Knight.

He says Knight has been doing all he can to demonstrate to the parole board that he should be released.

"(Knight) has wanted to be released on parole as soon as is practicable. He has made arrangements with his family for a place to stay," he told ABC local radio.

"We've been hoping that the Parole Board would be allowed to do its job independently as it should for every person in prison."