Some New Zealand Defence Force (NZDF) personnel just deployed to Australia's bushfire crisis may be headed for biodiversity-rich Kangaroo Island, where around 155,000ha of pristine land has been scorched.

Around 100 NZDF personnel were today flown across the Tasman to help Australia battle the unprecedented fires, now burning across several states.

The contingent includes two NZ Army combat engineer sections, three Royal New Zealand Air Force NH90 helicopters and crew and a command element to support the Australian Defence Force.

The support was in addition to the latest rotation of five NZDF firefighters deployed to bolster numbers of responders on the ground.

"One of things I know will add value to the Australian operation is that our people are light and mobile, and can be deployed in small aircraft and helicopters quite swiftly, and then can operate independently on the ground," Defence Minister Ron Mark told reporters today.

Mark suggested that some staff may be deployed on Kangaroo Island off Australia's southern coast, where about a third of the land area has been ravaged.

Space agency Nasa, which released satellite images of the devastation, described it as an "ecological tragedy", noting that around 25,000 koalas – or half the island's population – had perished.

"I can tell you this from talking to the troops deploying … they are all really looking forward to this mission and being able to do something constructive.

"Let's be clear, if we were facing a fire on this scale, we would definitely be needing help from Australia.

"We may have differences on the cricket field right now, but when it comes down to stuff that really matters, Australia and New Zealand have traditionally always leaned in and supported each other."

Mark couldn't confirm where the NZDF aircraft would be posted, saying they'd be sent as and where required.

He also said it was possible that more NZDF personnel may be deployed over coming weeks.

"As the situation unfolds … there may be a need to surge forward with some extra personnel, if we need other trade skills and trade groups in the deployment," he said.

"2 Engineer Regiment is gearing up for that, and we've got 12 New Zealand Defence Force firefighters on top of that."

Meanwhile, a further 21 firefighters today also departed New Zealand for Australia, bringing the number of Kiwi firefighters deployed since October to 179.

Mark spoke of the need to provide respite to personnel as the operation wound on.

"The sustainability of any operation is often dependent on how well you rest people and how you replace them to keep the operation going," he said.

"It's not going to be over soon – this is going to go on for quite some time, if you look at what is happening in Australia."

He also pointed out fires that had broken out on New Zealand's East Coast, and re-iterated the need for a new climate change risk assessment here.

"I think we need to start some forward thinking and forward planning for own sakes, as well."

One of our Hercules aircraft has recently departed Base Ohakea transporting an New Zealand Army contingent of Combat Engineers as well as a command element to support efforts in tackling the Australian fires.

The second of three NH90 helicopters has recently departed for Australia via an Royal Australian Air Force C-17A Globemaster III aircraft.