The strongest El Nino in nearly two decades has created tinder-dry fire conditions around the country, prompting a plea for Kiwis to heed restrictions now blanketing most regions.
While rural crews typically respond to around 3000 rural and vegetation fires each year, call-outs rates have been tracking above average because of dry El Nino conditions particularly in eastern and northern regions.
"The more important fact is we've had fires that have come much earlier and been much larger than normal," national rural fire officer Kevin O'Connor said.
Three times this season, the National Rural Fire Authority had taken the dramatic step of calling in special incident management teams to co-ordinate large-scale responses.
Tens of millions of dollars worth of damage had already been caused, with the driest part of summer still to come.
Last month, Marlborough's largest fire in 15 years destroyed around 1200ha of forestry land in the Wairau Valley and cost an estimated $30 million.
Mr O'Connor said the forest wiped out had been only years away from being ready for harvest, while just bringing the fire under control was estimated to have cost around $2 million.
It followed another large forest fire in Marlborough's Waikakaho Valley that destroyed around 400ha and also forced surrounding homes to be evacuated.
And near Masterton, a fire that raged across nearly 200ha of forest took around 100 firefighters a fortnight to extinguish.
In dry areas of the country, the El Nino system had elevated fire danger with the combination of strong winds, high temperatures and low humidity.
"When you get these conditions, the benefit from a bit of rain, like that we had after New Year's Day, doesn't last long," Mr O'Connor said.
"In parts of Central Otago, North Canterbury and Marlborough, the fire risk has started to jump up again quite quickly."
Across the country, scrub fire danger was currently rated either "extreme" or "very high" and crews were now regularly being called to small blazes.
Because conditions had made vegetation more flammable, fires moved faster and posed a greater risk to firefighters.
"It's critical that crews are well-trained, but that doesn't mean we undertake any unsafe operations - it's just not worth it."
Vegetation fires were typically triggered by camp fires, rubbish fires, land clearance and sparks from machinery like lawnmowers and weed-eaters.
But Mr O'Connor believed people had become more aware of risks and were "generally responsible".
"I think they realise that the costs they might personally incur, for the call-outs and putting the fires out, can be quite significant."
Under El Nino conditions, he expected restricted and prohibited fire seasons in many areas to be in place longer than usual, perhaps into April.
He encouraged anyone planning to light fires this summer to first get advice from their local rural fire authority.
The mainland Auckland region was presently in a restricted season, meaning a permit was required to light a open air fire, while a total ban remained in place in populated Hauraki Gulf islands.