Anaesthetic technicians at Rotorua Hospital have started their five-day strike.
The APEX union members are stopping work for 120 hours, until 8am on Saturday.APEX, is New Zealand's specialist allied, scientific and technical union.
This week's strike brings the total industrial action by the Lakes DHB technicians to nine 24-hour days since October last year.
They have been bargaining their collective agreement with the Lakes DHB since October 2017.
APEX advocate Luke Coxon said, "The DHB is postponing or cancelling hundreds of elective surgeries, at an estimated cost of hundreds of thousands of dollars."