Medical advisors at ACC have gone on strike this morning, saying the government agency is stonewalling any improvements to their collective employment agreement.
Employed by ACC, 39 senior doctors have held strike action from 8am until midday today.
Medical advisors want a one percent pay increase, redundancy provisions matching other staff and a statement acknowledging the health and safety of staff.
Association of Salaried Medical Specialists (ASMS) senior industrial officer Lloyd Woods said ACC have refused to even negotiate the terms.
"Our members are very, very frustrated, we expect better from employers than to just stonewall," Mr Woods said.
"Until we took the ACC to mediation over this matter, we didn't really have any response whatsoever to our claims than just no," he said.
In a statement from ASMS, one of the doctors striking, who wanted to remain anonymous, said it was the first time they took industrial action since becoming a doctor 28 years ago and starting at ACC 14 years ago.
"Why? Because ACC, the organisation charged with the prevention care and recovery of injury cares so little for its workers," the statement read.
"Sometimes you have to stand up and be valued."
However, ACC said they were happy to return to negotiations.
Negotiations stalled because the association was seeking terms above those offered to other employees, ACC said.
"In the meantime, we have contingency arrangements in place to minimise the impact the strike may have on client services," ACC said.
If both parties cannot come to an agreement, further strike action will be held next Wednesday.