In November 2010 Milat lured friend David Auchterlonie, 17, to the Belanglo State Forest - the scene of his great uncle Ivan's infamous exploits - and murdered the youth with a double-sided axe.

In handing down a 43-year sentence, with a non-parole period of 30 years, in June last year, Acting Justice Jane Matthews described the murder as an "adrenaline-fuelled thrill kill".

Milat, now 20, "tortured and tormented" his mate prior to striking him in the back of the head, Justice Mathews found, and later bragged about the crime to his mates and in a series of chilling jail-cell poems.

The last, terrifying moments of David's life were recorded on a mobile phone by another of Milat's friends, Cohen Klein.

Klein was also convicted of murder for his role as a supporter and facilitator of the crime, and was sentenced to a minimum of 22 years' jail.

He too is appealing the "excessive" nature of the sentence.

On Friday Milat's barrister, John Stratton, SC, told the NSW Court of Criminal Appeal that the sentence given to Milat was significantly out of step with other, equivalent murders.

"I'd like to ask a question of your honours: if the sentence imposed upon Milat was halved, could it be said to have been manifestly inadequate?" he said.

"In my submission the answer is no."

One of the three appeal judges, Justice Robert Hulme, replied: "For my part, Mr Stratton, that is a very bold submission."

Mr Stratton also submitted that Justice Mathews had erred in finding that Milat had tortured Auchterlonie.

"It is submitted that there's no evidence of torture in the way that term is commonly understood - that is, the infliction of pain over a long period of time," Mr Stratton said.

The physical blows prior to the fatal strike appear to have been limited to three blows with the side of the axe."

"So are you submitting that it's not torture because it was over a shorter period?" Chief Justice Tom Bathurst said.

Mr Stratton also argued that the sentencing judge had erred in finding that rather than motivated by anger during the murder, he had been "cold blooded" and pursuing a thrill.

He said that while the murder was "horrific" in nature, there was evidence that the case did not fall into the worse case category of murder as Justice Mathews had found, and that his prospects of rehabilitation were better than she had found.

But Justice Peter Hall pointed to Milat's prison poems as evidence against this.

"The applicants writing some nine months after the events might be characterised as reflecting enjoyment of the prospect of callous murder."

Counsel for Klein, Janet Manuell, SC, told the court that the distance between Milat's sentence and that of her client should have been greater.

"Milat was unquestionably the dominant offender," she said.

"It was Milat who obtained the weapon, organised for the victim to go to Belango, inflicted the injuries and bragged about it afterwards.

"The role of the applicant [Klein] was support and facilitation."

smh.com.au