Two firefighters were so exhausted during the SkyCity convention centre fire they fell asleep at the top of a 32m-high ladder while manning hoses to battle the blaze.
That's according to the New Zealand Professional Firefighters Union, which also said another two fell asleep driving home after their shifts ended,
Fire and Emergency New Zealand is investigating and region manager Ron Devlin said the organisation was aware of fatigue reports.
But Devlin said the safety of firefighters was paramount and at the forefront of all decision-making at an incident.
In a complaint to the union about management of the fire, seen by the Herald, a senior firefighter described how his colleagues were so exhausted from a lack of rest and food that they fell asleep eight storeys up the ladder on the first night of the fire.
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It took 150 firefighters four days to extinguish the New Zealand International Convention Centre fire, with 27 million litres of water poured on the blaze at the $700 million building in central Auckland.
The complaint alleges that firefighters were only provided relief after a senior firefighter realised a crew member had fallen asleep up the ladder and another refused to go back up - prompting him to shut down the operation.
By that stage some of his crew had been rotating through shifts at the top of the ladder without enough breathing apparatus for more than 12 hours, the complaint alleges.
"Because we were not relieved, we couldn't get to the canteen for any food or drink and no provisions other than some water was brought around to that sector."
SkyCity fire: Should have been out in two hours - union
At one point a firefighter left the scene and bought a large amount of food at his own expense to feed the crew, the complaint said.
"It was only after we shut the aerial [appliance] down that things started to happen as they couldn't afford to lose the crane.
"A second firefighter has since confirmed to me that he also fell asleep at the head of the ladder."
Other complaints seen by the Herald back up the fatigue concerns.
A station officer said he witnessed staff "absolutely shattered and falling asleep on the sidewalk", in the command unit and inside fire trucks.
"... I believe we put the crews' health and wellbeing at critical risk.
"The turntable ladder for example was positioned at full extension and tired, fatigued staff could have easily made a mistake causing catastrophic injuries."
The station officer said at one point he found an unmanned aerial appliance and it was two hours before the crew, who were having a break, were found.
"It soon became apparent there were no relief crews for the aerial [appliances] and the public sat and watched a $700m building burn while nobody had any idea where the crew was."
Concerns also included off-duty firefighters not being called to the event, no proper toilet facilities, poor handovers as well as FENZ rules around how many and which fire trucks respond to a high-rise building with sprinklers, given the convention centre's sprinklers were not complete.
NZPFU Auckland local president Sulu Devoe and local secretary Martin Campbell said the union raised concerns during a debrief with FENZ commanders on Wednesday.
He called the firefighters asleep up the ladder an "extreme case of fatigue" that was "very alarming".
"We do acknowledge that we have a 14-hour shift that we work but we're not expected to be performing hard, physical work for the entire 14 hours."
He claimed there were only three firefighters qualified to operate the cherry picker at the scene that night, with two needed at any one time, meaning they couldn't get a break without back-up.
"There's going to be a lot of lessons learnt from this we believe."
Devlin told the Herald FENZ was investigating the reports of fatigue but everyone played a part in monitoring exhaustion.
"Our firefighters do an amazing and brave job in some difficult circumstances.
"Everyone on the incident ground has a part to play in monitoring their own fatigue and keeping themselves and each other safe."
During the SkyCity response crews were rotated every five or six hours where possible, given meal breaks, food and water, and toilets were identified for FENZ personnel, he said.
"A fire on a scale like the Auckland fire required a lot of resource to extinguish.
"At the peak of the fire there were more than 130 firefighters working to put it out."
Devlin said FENZ had enough firefighters trained in operating aerial appliances.
"At any incident, we regularly review resourcing needs. At the SkyCity fire additional aerial appliance operators were called to duty as needed."
He said as with any major event, FENZ would be reviewing its response and would take any lessons into consideration.
"We're committed to resolving any issues raised from this incident and identifying any areas which could be improved for future."
Multiple investigations into the fire are continuing. SkyCity says the convention centre will be rebuilt.