Anaesthetic technicians employed at Royston Hospital have given notice of a 24-hour strike taking place at the end of July.
Technicians at Bowen and Wakefield hospitals in Wellington will also be taking part in the strike on July 27.
The hospitals are all owned by Evolution Healthcare, formerly known as the Acurity Health Group.
The anaesthetic technicians, who are members of APEX, have been in bargaining since May, but talks have broken down over pay amid a growing workforce shortage.
The company has offered 2 per cent increases per year for two years, while APEX was seeking 5 per cent per year.
APEX advocate Luke Coxon said New Zealand had an "acute shortage" of anaesthetic technicians, with surgeries now being routinely cancelled due to workforce shortages.
"Evolution Healthcare is chronically understaffed and struggling to recruit anaesthetic technicians," Coxon said.
"Our members are working nonstop, and gaps are being filled by locum agencies, whom the company has no qualms paying more than double what they pay their own staff.
"Despite the glaring need for a fair pay increase to enable recruitment, we were only offered a 2 per cent increase a year."
He said Evolution Healthcare were expanding and could afford a "reasonable" pay increase.
"More importantly they must realise they need to do so to ensure they have the anaesthetic technicians to staff their hospitals and provide surgeries."
The strike will result in nearly all surgery that requires a general anaesthetic being cancelled on July 27.
"Mediation will take place prior, and APEX is hopeful that an agreement can be reached, and the strike averted," Coxon said
In March, Royston CEO Sue Channon recognised the pivotal role that anaesthetic technicians had with each team member in the operating theatre.
"Anaesthetic technicians are vital to all operating teams, from assisting the anaesthetist and surgeon, they are quick to respond to unexpected changes that can occur during procedures," Channon said.
"They play an important role to expertly care for people of all ages, cultures, and medical status. The work they do is truly outstanding."
Anaesthetic technicians work mainly in operating theatres, providing skilled assistance to the anaesthetist.
They check and maintain the anaesthetic machines and other related equipment, ensure appropriate equipment and drugs are available, assist with inserting airway devices and venous/arterial cannulas, and act as advocates for patients.
While they work predominantly in operating theatres, they are called upon to work in any area where an anaesthetic may be given, including CT, MRI and radiology, ED and intensive care, and during cardiac arrest.