A woman who doused a childhood friend in petrol and set him on fire in her backyard after he joked she should be in the kitchen baking scones has lost her bid for a shorter prison term.

Corbie Walpole argued that the judge who jailed her for a minimum of four-and-a-half years had failed to properly consider her mental health, including a PTSD diagnosis stemming from the crime itself. 

Walpole claimed Jake Loader had made misogynistic comments to her before she poured five litres of lawn mower fuel over his head and used a cigarette lighter to turn him into a human torch.

An expert estimated Walpole had consumed 23 to 35 standard drinks over 12 hours and would have had a blood alcohol level between 0.22 and 0.38 when she set Mr Loader alight.

The 25-year-old suffers flashbacks of the drunken, drug-induced atrocity when she smells petrol or hears a lawn mower running at Dillwynia Correctional Centre in Sydney's north-west.

Walpole pleaded guilty in the NSW District Court to one count of burning, maiming, disfiguring or disabling a person by use of a corrosive fluid and has been behind bars for the past 13 months.

Judge Jennifer English rejected any suggestion Walpole had been provoked when she attacked 22-year-old Mr Loader in an act of 'destructive and horrifically painful violence'.

Judge English jailed the electrician for a maximum term of seven years and six months last May - but Walpole claimed that sentence was too long.

Walpole, from Howlong, near Albury on the NSW-Victoria border, took her case to the Court of Criminal Appeal (CCA), which on Wednesday ruled her prison sentence was warranted.

She had alleged Judge English denied her procedural fairness by rejecting the evidence of a forensic psychologist over the link between an existing mental illness and her crime.

Walpole also alleged Judge English failed to take into account on sentencing a 'relevant consideration' that she had developed PTSD 'as a result of the offending conduct'.

The CCA agreed that Judge English had denied Walpole procedural fairness by not raising during sentencing the forensic psychologist's evidence about her existing mental illness.

But having considered the case as a whole, Justices Julie Ward, Richard Cavanagh and Richard Weinstein concluded that Walpole's four-and-a-half year sentence should stand.

The court also found that Walpole experiencing PTSD - 'consequent upon [her] realisation of what she had done and the impact it has had upon her' - was not a form of extra-curial punishment.

The judges noted the development of PTSD by an offender after the commission of an offence was 'neither unusual nor surprising'.

'It may flow from the realisation of what the offender has done and the consequences for the offender,' they found.

'It is sometimes associated with remorse. It is plain that, in this case, the applicant is remorseful. She thinks about what she did every day. 

'She has intrusive thoughts relating to, and can be triggered by, petrol. Her sleep is disturbed and she has an entirely negative outlook about herself.'

Walpole had faced a maximum possible sentence of 25 years for setting Mr Loader ablaze as he sat on a chair in her backyard at Howlong, about 30km west of Albury, on January 6, 2024.

Judge English found Walpole had begun drinking about 5pm - downing bottles of cider, schooners of Canadian Club and Bacardi and cola, and cans of Hard Solo. 

Walpole claimed Mr Loader had been antagonising her throughout the evening and she finally snapped at about 4am after he told her she should be in the kitchen baking scones.

'He told me to go to the kitchen where I belong because I'm a girl,' Walpole said. 'I gave it back to him and called him a misogynist.

'He was really pushing my buttons. I was feeling overwhelmed by [Mr Loader's] presence, and I didn't know what to do.'

Walpole, who had been taking cocaine, got up from an outdoor table, went to her garage and collected a five-litre jerry can of petrol. She returned to the table, poured the fuel over Mr Loader and waved a cigarette lighter around.

'I'll do it,' Walpole said. 'I'll do it.'

Mr Loader replied: 'Go on, do it.'

Walpole carried out the threat and Mr Loader was immediately engulfed in flames.

Mr Loader, who suffered third-degree burns to 55 per cent of his body and less severe injuries to an additional six per cent, underwent 10 operations and spent eight days in a coma.

He had worked mustering cattle in Queensland but after the attack could no longer expose his skin to the sun and his body struggled to regulate its temperature because his sweat glands were burned off.

Walpole, who pleaded guilty to assault occasioning actual bodily harm after a scuffle with a pub bouncer in 2021, had been abusing drugs and alcohol from late 2022.

She had been in a failing relationship which left her feeling trapped and depressed in early 2024, but admitted that was no excuse for setting fire to Mr Loader.

'Jake didn't deserve what happened,' she told the court.

The CCA found that while Walpole's depression played a part in her offending, it had not reduced her moral culpability 'to any great extent'.

'The objective seriousness of the offence was high,' the court ruled. 

'This was a deliberate act of violence inflicting serious harm on the victim and posing a risk to the others present at the time. It was unprovoked.'

The judges said Walpole's offending was 'not premeditated and was impulsive', her actions were 'quite deliberate', and she had time to refrain from the final step of striking the lighter.

'We do not accept that [Walpole] did not foresee the consequences of striking the lighter after dousing petrol on the victim,' the court found. 

'The threat that she would "do it" can only have meant that she understood, even in her profoundly intoxicated state, the likely consequence of applying flame to petrol.

'This matter involved serious offending which calls for strong denunciation. The victim must have been in excruciating pain and suffered horrific injuries.'

The judges accepted Walpole was otherwise a person of good character, was unlikely to re-offend and had 'excellent prospects' of rehabilitation.

'We also accept that the applicant has experienced and continues to experience PTSD which arose as a result of the offending which may make her time in custody more onerous,' they found. 

Walpole's earliest possible release date is November 21, 2029.