Thousands of prison officers protesting against the sentence of an inmate who assaulted four colleagues have been ordered to stand down from striking.

Workers at Cessnock Correctional Centre, in the NSW Hunter region, and Bathurst Correctional Centre, west of Sydney, walked off the job in a snap protest after a local court gave Cameron Welsh what they deem is a "slap on the wrist".

Welsh assaulted four prison officers at the Cessnock prison in an incident earlier in 2025, with all four taken to hospital and two left unable to work again.

Their colleagues across 34 other jails walked off the job, sending prisons into lockdown, and were planning to continue to their protest on Friday.

Prison staff have been ordered back to work following a snap strike over a magistrate's sentence. - AAP file

In an urgent Industrial Relations Commission hearing on Thursday, the NSW government argued the local, district and supreme courts would be crippled with the transfer of inmates from custody thrown into disarray.

Commissioner Janet McDonald agreed and decided the more than 5000 members "must immediately take steps to cease organising and refrain from taking any industrial action".

She is due to hand down her reasons on Friday, with the ruling welcomed by a relieved government.

NSW Corrections Minister Anoulack Chanthivong said community safety remained his top priority while acknowledging the officers' frustrations.

"I understand why correction officers are angry," he said in a statement after the independent umpire's decision.

"Working in a prison is a tough job at the best of times and correctional officers put themselves at risk to keep us all safe."

He described the bashings which left the officers with bruised and lacerated faces as disgusting and cowardly.

On Wednesday, a magistrate did not add extra time to 26-year-old Welsh's current sentence, leaving prison workers incensed and concerned over their safety.

"This tells the community it's OK to bash prison officers, that you won't be punished if you do and you'll be able to return to the community," Public Service Association president Nicole Jess said.

"In giving Mr Welsh a slap on the wrist this magistrate has delivered a slap in the face to every prison officer in this state who keep our community safe."

Jails on Thursday were operating with a skeleton staff.

Welsh received a three-year community corrections order after he was convicted of four counts of assaulting a law enforcement officer and one count of intimidating with the intent to cause fear or physical harm.

Chanthivong plans to write to the Office of the Director of Public Prosecutions seeking an appeal of Welsh's sentence.