A radicalised prisoner who allegedly bashed a fellow inmate and carved a jihadist slogan into his head should be rehabilitated rather than isolated in a high-security jail, a counter-terrorism expert says.

Key points: Inmate moved to SuperMax prison after alleged attack

Inmate moved to SuperMax prison after alleged attack Isolation contributes to radicalisation, expert says

Isolation contributes to radicalisation, expert says Expert calls for rehabilitation environment for radicalised inmates

Expert calls for rehabilitation environment for radicalised inmates Public Service Association says Government "pushing us to take prisoners well beyond capacity, could be similar attack in future"

It is alleged the 18-year-old poured boiling water over the inmate's head and carved "e4e" — which also stands for "an eye for an eye" — into his forehead.

The 40-year-old prisoner was treated in hospital after the attack at Kempsey prison on the NSW north coast last week, and is due to be transferred back to jail in the next few days.

Meanwhile, the teenaged radicalised inmate has been moved to the SuperMax prison in Goulburn, but counter-terrorism expert Dr Clarke Jones said that was not the right response.

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"If they're placed in high security and they're isolated or segregated, often that contributes to someone who may have already exhibited signs of radicalisation," he said.

"It sometimes compounds the feeling of isolation, marginalisation or the original reasons we've got them there in the first place."

Prisons should help inmates, expert says

Instead, Dr Jones suggested prisons should create environments to help radicalised inmates or those on terrorism convictions.

"We need to create the environment that fosters and enhances the chance for rehabilitation and that doesn't happen in maximum security prisons," he said.

Dr Jones used the example of Khaled Sharrouf who was in prison for five years, went to fight for Islamic State in Syria and was killed.

"He had significant mental health issues and they were obviously not dealt with properly in his time of incarceration," he said.

"He certainly wasn't in an environment to create any type of rehabilitation ... then he was released a worse person."

A Corrective Services Department spokesman said "a couple of jail-made weapons" were found during a search for contraband at the maximum security section of Goulburn jail this morning.

Victim was not a soldier, Corrections Minister says

In a written statement responding to questions from the ABC, NSW Corrections Minister David Elliott said he had made enquiries into the hospitalised prisoner's claim that he served in East Timor.

"During an interview with Corrective Services this morning, the man said he was in the Army Reserve for approximately eight years although he was unclear on which units and the timeframe of his service," the statement said.

"He said he had not served in the Australian Regular Army or on overseas military operations in East Timor or anywhere else.

"Furthermore, the man lost sight in his left eye during a childhood accident which would have made any military service unlikely.

But he said it was "important to note that the man's background does not change the seriousness of this incident".

Prisoners pushed into system well beyond its capacity

A spokesman for the Public Service Association, which represents prison guards, Steve McMahon, said there was no information in the system that would have raised the alarm about placing the two prisoners together.

"The Government is continuing to push us ... to take prisoners into the system well beyond the capacity. We've been requested on a number of occasions now to take three prisoners per cell in some locations."

He said it was possible there could be a similar attack in the future.

"On a number of grounds, yes, it's possible that we may have more unrecognised, self-styled administers of justice amongst radicalised inmates who want to do this," he said.

"And then there's always the risk that two grown men, unrelated grown men, placed in a cell the size of an average backyard garden shed, will not get on and they will fight. So it's a matter for us balancing out the best-case scenarios."