Navigation radar interference from HMAS Canberra, the Royal Australian Navy's largest warship, disrupted 5 GHz wireless access points on Wednesday as it sailed through the Cook Strait.
The interference triggered in-built switches in the devices that caused them to go offline, ABC News reported - a safety precaution to prevent wireless signals interfering with radar systems in New Zealand's airspace.
Luxon told RNZ this morning he was yet to have an explanation how the situation was allowed to happen, but he was "sure" Defence Minister Judith Collins would find out.
He said it was not a "deliberate" act from the Australians.
"Look, we are very pleased that they're here. They are our only ally. We work very closely with the Australians, as you know, I'm not sure what's happened here. Again, that'll be something the defence minister will look into."
Asked if it had exposed a vulnerability in our communications network, Luxon said it was "the nature" of it.
"There's a whole bunch of technology… in the defence space and the cyberspace and how wars are being fought, and will be fought in the future will be a big component of it…
"Judith Collins will be checking into that and understanding exactly what has happened there, but I'm very proud of that relationship. I'm very proud that they're here. It's great that they've come."
The blackout came the same week "human error" knocked out fibre-based internet to much of the lower North Island.
Communications Minister Paul Goldsmith told RNZ last week he would be discussing the Australian warship situation with officials.
Relationships with China, US
Also last week, two former prime ministers and an ex-governor of the Reserve Bank put their names to a letter questioning the government's foreign policy - in particular "positioning New Zealand alongside the United States as an adversary of China".
It was signed, among others, by Helen Clark, Sir Geoffrey Palmer and Dr Don Brash, questioning whether New Zealand was risking its economic and trade relationship with China by aligning itself closer with the US.
"Like 192 other countries, we've got an independent foreign policy. There'll be lots of different views on foreign policy, I get that," Luxon told RNZ.
"But, you know, frankly, my job as prime minister is to advance our national interests - that is both… around our security and our economic interests. And I think you've also got to acknowledge that the strategic environment from 25 or 35 years ago is very different from what we have today, and it will continue to evolve."
He said he disagreed with the view that working more closely with the US on defence, under the adversarial Trump administration, would sour New Zealand's relationship with China.
I think, you know, we have important relationships with both the US and China. We will make our own assessment based on our own needs, as to, you know, how we navigate those relationships.
"But in both cases, you know, we have, you know, deep engagement and cooperation. We also have differences with the US - we've raised concerns around tariffs. With the Chinese, we've raised concerns around cyber attacks on our parliamentary system."
