Local officers walked off the job Friday in support of colleagues at Goulburn Supermax following several assaults on officers by Supermax inmates last week and a recent judge's decision to reverse Bassam Hamzy's 20-month sentence extension for bashing a Supermax prison officer in 2017.

Officers were angry over safety, security, and staffing, calling for action from the Corrective Services Commissioner, Corrective Services Minister, Attorney General and NSW Premier.

More than two-thirds of prison officers followed suit in walking off the job. The union said that in the past week, one attack had seen a guard hospitalised, another assaulted with faeces and urine, and a third attack where two officers were bashed, one needing stitches above his eye.

Officers remained on strike Saturday, despite the Industrial Relations Commission ordering the Public Service Association and Professional Officers Association members back to work.

Up to 3000 prison officers across NSW had gone on strike.

The South Nowra complex, home to around 800 inmates, after the recent opening of a new 200-bed minimum-security wing, remained in lock down on Saturday.

Executive staff manned the local facility with prisoners remaining in lockdown. It is understood they were being fed meals in their cells.

The South Nowra prison is undergoing a major expansion with an additional 160-bed maximum-security wing to be opened  for operation in the coming months.

When complete the facility will be home to 1050 inmates, almost a third more than prior to the upgrades.

Close to 90 of the staff attended a special meeting outside the South Nowra Jail facility on Saturday afternoon.

Staff had originally agreed to support their colleagues and stop work until Monday.

Staff were told at Saturday's meeting agreement had been met with the government.

They voted to return to work from 8am Sunday, March 10, but further meetings would be held on Monday between the Association's Prison Officers Vocational Branch and Corrective Services.

The strike saw courts across NSW brought to a standstill due to offenders or defendants being unable to be remanded in custody.

NSW Corrections Minister David Elliott and Attorney General Mark Speakman have thrown their support behind correctional officers.

In a joint statement Mr Elliott and Mr Speakman said the NSW Government stands with hardworking correctional officers who have one of the most dangerous jobs in the state.

"Their safety is our priority," the statement said.

"Urgent advice has been sought from the Office of the Director of Public Prosecutions on whether it will appeal the recent District Court judgment in relation to the matter of Hamzy.

"Even if the Director of Public Prosecutions does not appeal, or an appeal is unsuccessful, then a re-elected Liberals and Nationals Government will amend the legislation to ensure any loophole is addressed and the legislation is strengthened,

"Meaning officers will enjoy the full protection of the law and their safety is enhanced."