District health boards say patients are being harmed by the "dirty" industrial tactics of unionised radiographers and laboratory workers and have asked the Government to "review" the right of health workers to strike.

The DHBs have listed potential harms to patients caused by the current industrial action, including two patients whose scans were deferred and have now been diagnosed with inoperable liver cancer.

"It is not known if this would have been treatable if the scan had been done at the time requested two weeks previously," the DHBs said.

At a press conference in Wellington today, senior DHB bureaucrats and doctors slammed the Medical Laboratory Workers Union and the Association of Professionals and Executive Employees, which represents radiographers.

"Enough is enough", said Northland DHB chief executive Karen Roach, calling for an end to the two unions' months-long campaign of partial, and occasionally full, strikes.

Capital and Coast DHB's chief medical officer, on behalf of the chief medical officers of all 20 DHBs, wrote to Health Minister Tony Ryall to explain "the risks and harms" to patients from the rolling industrial action.

"We note that other public safety workforces such as the police have alternative mechanisms, for example compulsory arbitration.

"We call on Government to urgently consider our concerns, and to move to review the current processes allowing health professionals to strike and thus compromise patient safety."

Hutt Valley DHB chairman Peter Glensor said the legal requirement for the union to provide life-preserving services was not designed to cope with the unions' tactics of sustained partial strike action.

"It is very much dirty pool in our eyes."

The DHBs said Hutt Valley expected to screen 2800 women with mammogram breast x-rays from July to September, but had been able to screen just 1400, because of the industrial action by radiographers. This raises the question of delays in detecting possible breast cancers.