A New Zealand firefighter who helped tackle the Australian bushfires in November last year says new crews being deployed today will face unprecedented and unpredictable conditions.
Another 21 New Zealand firefighters - four five-person crews and a team leader - are departing today, joining a liaison officer who left yesterday for a 10-day deployment after the Australian government formally requested help.
This latest deployment brings the number of firefighters sent from New Zealand to 179 since late October.
Read more on the Australian bushfires:
Two people die in bushfires that ravaged large parts of Kangaroo Island in South Australia.
Bushfires threaten dozens of communities in Victoria, a southerly cool change fans problems in NSW, and more than a third of Kangaroo Island has burned in South Australia.
Members of the Royal Family have said their "thoughts and prayers" are with Australians affected by the massive bushfires.
Australia's Prime Minister Scott Morrison has been condemned for releasing videos on social media advertising his government's response to the bushfire crisis.
The New South Wales rural fire service and fire authorities in Victoria fear hundreds of properties have been destroyed by the bushfires.
A yellow haze covered Auckland, as smoke from the Australian bushfires drifted over the North Island.
For Auckland deputy principal rural fire officer Scott Marchant, it will be the second time in two months battling fires in Australia.
"There will be a lot of chaos, a lot of upset people," he told Summer Report as he prepared to leave. Last time fighting fires in November was like "nothing he had ever seen before".
"Just the sheer size and the devastation. I've been over to America, Canada, and not even seen anything like what's been going on in Australia.
"It's tripled - maybe even more - the size than it was when I was there, and it's been just huge devastation. Very sad."
The most risky factor facing the firefighters in their 10-day deployment was the sheer unpredictability of a raging fire.
"Heck of a lot of risk because fire is unpredictable, especially with the conditions that they've got over there and the changes of the wind direction and the wind speed."
The New Zealand contingent is highly skilled and has plenty of experience, he said.
"We have got some very highly trained firefighters going over that are fully knowledged-in on fire behaviour, so yeah, nah, they'll do good."
Australian firefighters have this week used a break from searing temperatures to strengthen containment lines around huge wildfires burning in the country's southeast, as the financial and environmental costs of the crisis mounted.
But the New Zealand contingent are likely to be deployed to help just as temperatures ramp up again around Friday, sending the fire risk soaring again.
The latest official data showed that more than 10.3 million hectares (25.5 million acres) of land across the continent - an area the size of South Korea - has been razed by bushfires in recent weeks.
Images from the Himawari 8 Japanese satellite and NASA's Earth Observatory showed plumes of smoke from the fires reaching as far as South America.
Firefighters on the ground were making the most of a few days of cooler temperatures in the southeast of the country to prepare for a forecast return of heat and wind later this week that is expected to spur existing blazes and spark new ones into life.
Marchant said he had watched video footage of Australian firefighters forced to shelter in their trucks as they were engulfed in flames. They all survived.
"It was definitely jaw on the floor material.
"I wouldn't want to be in their situation - and they probably weren't in that situation until they had a change in the weather or change in the fire behaviour.
"That's how instantaneous it is. They were probably coming out not even knowing that was going to happen and then, boom, it's just happened in front of them."
Firefighters found themselves with two roles in the midst of overwhelming tragedies like the bush fires - fighting the fires and then comforting the ravaged communities.
"It is sad to see the devastation on their faces. I have been through it. I have lost my own property to a fire, I know what they're going through, and the worst probably bit about it for them is they know it hasn't happened yet but it's coming and there's probably nothing they can do about it.
"It's probably been on their mind for months and they're just tired, you know."
He said the firefighters working to protect those homes, who are mostly volunteers, needed support - including psychological support to look after their welfare.
The New Zealand team, which includes trained firefighters from Northland, Auckland, Thames, Bay of Plenty, Taranaki, Nelson, Canterbury, the West Coast and Southland, will be departing this afternoon.