Three days of strike action will be held on Monday 24, Wednesday 26 and Friday 28 August by UNISON members, including nurses, clinical support workers and housekeepers, at Salford Royal Hospital, Royal Oldham Hospital, Rochdale Infirmary and Fairfield Hospital in Bury.

UNISON North West regional organiser Kevin Dolan said: ‘Those at the top of NCA have shown a lack of leadership and made their disregard for their staff clear.'

The union said an offer to resolve the dispute was initially tabled by NCA but withdrawn before discussions could take place.

The row centres on the use of an outside agency – NHS Professionals – to manage overtime.

UNISON said in some cases staff earned less than they would on a normal shift, with some missing out on more than £80 per shift.

Gertie Nic Philib, chief people and strategy officer at NCA, said: ‘We have received formal notification that our theatre colleagues will be taking part in industrial action next week. We are preparing for this period of action and are working hard to minimise disruption to services and the patients who rely on our care.  

‘Our focus throughout this period is on maintaining safe services, supporting colleagues and ensuring that patients requiring urgent, emergency and other time critical care continue to receive the treatment they need.   

‘While we have not been able to reach agreement, we respect our colleagues' right to take lawful industrial and will continue to engage constructively and work together in the interests of patient safety. 

‘We apologise for any uncertainty this may cause. People should be assured, that should any changes need to be made with their care, we would always contact them directly.'