Binse, known as "Badness" and notorious for his history of armed robberies and for a 44-hour siege at his Keilor East home, is currently serving an 18-year jail term that was imposed two years ago for offending in the first half of 2012, which included robbing two Armaguard officers of $235,000 and the siege, during which he fired shots at an armed police vehicle.

He is also awaiting sentence for a string of hold-ups between 1988 and 1991, which netted him about $390,000.

Binse, 47, has already spent about 30 of the past 33 years in some form of custody, including a stint in Pentridge's H Division as a teenager.

Dressed in a black collared shirt and blue jeans and surrounded by four guards, Binse sat in the Court of Appeal on Tuesday as his lawyer, Greg Hughan, said his client spent only an hour a day outside his cell and had no contact with other prisoners, given previous threats against him, his risk of self-harm and his history of escapes.

Mr Hughan said Binse was a "psychologically damaged individual" whose current jail term was an excessive and crushing one that "would drive him to despair and lose hope of a post-sentence" life.

"The prospect that someone is going to spend a good part of 18 years and two months in lock-up for 22 or 23 hours a day ... is really something that is so far out of the norm of what we expect prisons to be. It should have been reflected in the sentence," Mr Hughan said.

"His situation is a bleak one from an objective point of view."

On March 19, 2012, Binse waited in hiding outside the Westside Tavern in Laverton and pointed a shotgun at two Armaguard officers and demanded their bag of cash. He had climbed a ladder behind a wooden fence to catch the guards by surprise.

Two months later, Binse pointed a gun at a police officer in the Niddrie La Porchetta pizzeria and fled to his home.

The following day, on May 21, 2012, he barricaded himself in and kept police at bay for almost two full days, until they fired tear gas canisters into the house and he came outside and was arrested.

Mr Hughan said the Laverton armed robbery had a degree of planning but lacked sophistication, as Binse was caught on a CCTV camera, hired a getaway van in his adopted surname Pecotic and later dumped the van and a motorbike where they would easily be found.

But prosecutor Chris Boyce, QC, said Binse took the guards by surprise at gunpoint, took their weapons and that the hold-up was getting towards "as bad as it could get".

Mr Boyce said Supreme Court Justice Terry Forrest had imposed a stern sentence, but within the range, and took into account Binse's failing mental health and guilty pleas.

Mr Hughan said Binse had made several suicide attempts in recent months and wanted to instruct young people to steer clear of crime, which would "make him a better person".

The appeals court judges will rule at a later date.