NZPFU Whangārei vice-president Jared Bailey told of the region's professional firefighters becoming burnt out from long hours and low wages.
Northland paid firefighters, based in Whangārei, had been working double-time to cover a shortfall of seven staff.
"We're supposed to have 39 in our establishment but we have 32," Bailey said.
"We've always got enough firefighters on duty but that means firefighters, since about Christmas time, have been averaging 70 to 80 hours a week to cover those positions."
A usual roster entails an average of 42 hours per week based on two-day shifts followed by two-night shifts, then four days off. Day shifts are 10 hours long and night shifts 14.
Bailey said the number of professional firefighters in Northland was the same as in the 1980s despite the large population growth.
"We're spending a lot of time away from family and loved ones.
"We really care about our job and care about our communities but we're not getting that same care from Fenz," he said.
Adding to firefighters' woes are the low wages offered by Fenz.
Currently, a trainee firefighter earns roughly $46,000 annually. The base salary for a qualified firefighter is $58,400 and a senior firefighter takes home $65,000 per annum.
The union has asked for an 18 per cent pay rise over three years. Fenz countered with an offer that meant more than two-thirds of members would receive a 1.5 per cent pay rise lasting for two years, union national secretary Wattie Watson told RNZ.
Watson said firefighters hadn't had a pay increase since July 1, 2020.
Bailey believed Fenz had lost its appetite for competitive salaries in the job market as a way to attract people to the role.
"People are now moving onto greener pastures as there's more money elsewhere," he said. "Fenz just haven't kept up with the market."
Bailey described how professional firefighters were returning to their previous roles, often in trades.
Adding to the powder keg was the nationwide issue of ageing vehicle fleets and Fenz's lack of action in the push for presumptive legislation - so firefighters had less of a rigmarole to prove cancer diagnoses were work-related.
Bailey was saddened to see current and former firefighters receive a cancer diagnosis knowing they were without the support of Fenz.
"Fenz haven't been listening," he said. "It's definitely frustrating ... It's more like they've got their heads in the sand."
The exact details of the strike action remained under wraps at edition time but Watson did hint that it may escalate to firefighters being unavailable.
Fenz says the organisation has endeavoured to understand the priorities for NZPFU members and how available funding can best be used to achieve these.
Chief executive Kerry Gregory told RNZ there had been a lot of work done together to create what they consider to be a really fair offer.
Overall, staff would receive a 3.3 per cent increase, which when divvied up could bring an 11 per cent pay rise for some junior firefighters and a 7.5 per cent increase for the two grades above.
However, the union reported 99.3 per cent of its members had voted to reject Fenz's offer.
Gregory responded to the union's claims about staffing remaining stagnant since the 1980s by saying they used "alarmist language".
He said variations in staff numbers had occurred since 1980 but staff levels were sufficient to provide the service needed in New Zealand.
