Radiation oncology workers are planning strike action in their pay dispute against six district health boards.

Medical physicists from four DHBs will begin strikes this week, and workers at another two DHBs will start striking next week.

The DHBs claim vacancies are low and waiting lists are under control.

But Association of Professionals and Executive Employees advocate David Munro says DHBs have their heads in the sand.

He points to a recent survey of radiation oncology workers, every responded said they were planning to find work overseas.

David Munro says they would earn 30 to 50% more if they worked in Australia.

"If we don't do something to match those salaries, then New Zealand in a very short of time will not be able to run the service to the extent that we currently do."

His view is that our Government pays to train them but won't pay to keep them.

"We've got a situation now where New Zealand taxes are really paying for cancer treatment in Australia."