All cancers should be recognised by ACC (Accident Compensation) as occupational hazards, the firefighters' union says.
The World Health Organisation's cancer research branch has defined firefighting as a Group 1A carcinogenic risk, the highest rating.
The NZ Professional Firefighters Union said cancer is the greatest killer of firefighters globally, but many struggle to get it covered by ACC in New Zealand.
And despite the cancer risks, emergency responders continue to work.
The union said firefighters' occupational cancer risk should be recognised by the government in legislation.
It also wants Fire and Emergency NZ (FENZ) to recognise the cancer risks, during union negotations.
The union's national secretary Wattie Watson said firefighters were still willing to get out there and from do their jobs, and deserved better.
"These men and women are extraordinary, not only do they know of their high risk of cancer, if we diagnose it early enough and they get the treatment that they need, they tend to want to come back on the trucks".
The International Agency for Research on Cancer researchers' finding and classification was the most significant development since firefighters started campaigning in 2013, Watson said.
"Firefighters in Canada, in America, in Australia, Norway recently, had their occupational cancer recognised through presumptive legislation, and the New Zealand firefighters deserve it as well."