Eighteen elective surgeries have been postponed at Whangārei Hospital due to a 24-hour strike by anaesthetic technicians in protest over better pay and working conditions.

About 21 anaesthetic technicians and three trainees joined more than 200 colleagues from across New Zealand from 7am today in the industrial action that ends at 7am tomorrow in an effort to receive a fair offer from Health New Zealand.

They will stay away from work during the industrial action. The only exception will be during emergencies.

They are members of the Association of Professional and Executive Employees (Apex) working in hospitals at Waitemata, North Shore, Whangārei, Tauranga, Whakatāne, Wellington, Hutt, Kenepuru, Rotorua, Christchurch, Dunedin, Hawke's Bay, Southland, Nelson, Palmerston North, Waikato and Taranaki.

General manager surgical and support services at Health NZ in Northland Mark McGinley said his staff would endeavour to reschedule the 18 postponed elective surgeries within the next one or two weeks.

Apex senior advocate Luke Coxon said the new offer received early this week would still see Apex-affiliated technicians falling behind their colleagues that belonged to another union.

"You can't perform most surgeries without an anaesthetic technician there so the strike will be pretty disruptive.

"The employer knows what they need to do to avoid this disruption, and that's give us a reasonable offer on salaries that does something to address the increased cost of living for our members."

Health NZ spokeswoman on employment relations Rosemary Clements said the Government acknowledged the tremendous work being done by the entire health workforce at an incredibly trying time.

"Therefore, it is hugely disappointing APEX has refused to even show its members our latest offer which we believe could have prevented strike action at a time when hospitals are under huge pressure from Covid, flu, staff illness and high occupancy.

"A comprehensive pay offer has been made that would align their salaries to the majority of Anaesthetic Technicians who are represented by the PSA."

Clements said a third of about 600 anaesthetic technicians at hospitals around the country were members of Apex which was using strikes to get settlements higher than colleagues who were members of other unions and performed similar work.

The timing of the strike action in the midst of the winter peak and a growing Covid infections would put additional pressure on the health system, she said.

Clements said hospitals would notify patients directly if elective and other community services needed to be deferred.

"Emergency and essential services will be available and if someone does need urgent hospital care, they shouldn't delay getting help."

Anaesthetic technicians are essential members of the surgical team. They work mainly in operating theatres, providing skilled assistance to anaesthetists.

Anaesthetic technicians 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 anaesthetic technicians 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 arrests.

- Imran Ali, Northern Advocate