Medical experts say more cancer patients will die if radiologists don't get better support.
Nearly 1100 DHB-employed medical imaging technologists are set to strike for 24 hours at the end of the month. The employees are responsible for identifying and diagnosing cancer, and are struggling with high demand.
APEX union national secretary Deborah Powell says the real victims are the patients.
"If it continues, we're likely to see longer waiting times, problems with diagnosing cancer in a timely-enough manner."
She says negotiations have ground to a halt. Vacancy rates are as high as 30 percent in some areas.
"It's hugely stressful for the team," said Dr Powell. "They do their best and try to get through all the patients that are waiting to be seen, but we can't work at that pace all the time - and that's what's being asked of these people in too many areas."
Dr Powell said some staff have had pay cuts that amount to $43,000 over six years.
"The employer's current offer is simply just not going to cut the mustard for the radiology team. We're also being faced with clawbacks."
New Zealand has a shortage of medical imaging technologists. Government data suggests they have a starting salary of about $57,000, rising to about $98,000 for people with more than six years' experience.