A prison operator has denied 1,000 prisoners in Australia's largest jail are likely to be confined to their cells for the duration of a 48-hour strike.
Prison officers at Clarence Correctional Centre near Grafton have been locked in a pay dispute with the facility's multinational operator Serco for more than 18 months.
The latest industrial action, which started on Wednesday, is the third time in a month staff have walked off the job.
The Community and Public Sector Union (CPSU) had said in a statement it expected inmates at the jail, which includes a maximum security wing, would be confined to their cells for two days and two nights.
Brett Collins, a coordinator for Justice Action, which represents prisoners, said inmates had already been locked down continuously during the COVID period.
"Our prisoners are locked into their cells already for periods like 16 hours a day," Mr Collins said.
"Time out is very precious when they can go to education, they can actually learn some skills, talk to one another, get out in the fresh air and have some exercise.
"So to have this restricted … has a very significant effect on prisoners."
The planned strike comes after union members rejected an 11th-hour offer by Serco to raise base pay rates but cut overtime rates.
"After hearing for two years that there was no money available, for Serco to come back to the table at the 11th hour just before a major industrial stoppage to say there is, has been greeted with a fair bit of scepticism by members," CPSU branch assistant secretary Troy Wright said.
Mr Wright said prison officers barely had time to digest Serco's offer made on Tuesday and therefore was not surprised it had been rejected.
Workers were not impressed by the proposed cut to overtime rates, he said.
"Overtime is a key component of prison officers' current take-home pay as Serco has difficulty recruiting and retaining staff," Mr Wright said.
Serco defends pay offer
In a statement, Serco managing director Michael Strickland said the company was disappointed yet another offer had been rejected.
"The current offer is an increase of around 15 per cent to the current base rate of pay, on top of the 8.5 per cent already paid last year," he said.
"In some cases that is an uplift of 23.5 per cent.
"This is a more than reasonable pay increase."
Mr Strickland said Serco had been "fair and reasonable throughout negotiations" and had worked "in good faith with the union and employee representatives in order to reach a generous agreement".
In an additional statement to the ABC, a Serco spokesman said "appropriate staffing levels to ensure the safety and security of the inmates accommodated at the centre has been maintained" during the strike.
"This includes sufficient custodially trained staff to support the majority of inmate areas to have time out of cell.
"We have an operational response plan in place to ensure the safety and security of the centre is maintained and there is minimal operational impact."
Greens spokesperson for Corrections, Sue Higginson, said the strike action at the privately run prison was indicative of problems confronting the entire sector.
"The NSW government set a target of needing 800 new [Corrective Services] recruits for this year ... only 360 have completed the training and 80 per cent of those are based in metropolitan regions," Ms Higginson said.
Corrections Minister Geoff Lee has declined to comment on the strikes.
His office told the ABC it was a private facility and therefore a matter for Serco.
