Photo: Gorodenkoff Productions OU / 123RF
Hospital-based MRI and nuclear medicine technologists have stopped work for four days from 6am Friday morning.
Their union, Apex, said they were striking because of failures by Health New Zealand to address pay claims.
The difference between public and private pay rates was more than 30 percent, it said.
Apex said life-preserving services were in place to ensure there were appropriate levels of care as more than 200 people strike over four days.
MRI and Nuclear Medicine Technologists to walk off job over pay
Apex advocate Abbey Hebson said Te Whatu Ora could not retain staff and was having to outsource scans.
"Over 30 percent of MRI & NM scans are outsourced to private radiology providers because Te Whatu Ora does not have the capacity to perform these scans in house."
She said outsourcing cost $20 million last year.
"It would be a better use of money to instead invest into Te Whatu Ora's own staff in order to future proof the workforce and keep a public MRI & NM service going."
Te Whatu Ora/Health New Zealand has been contacted for comment.