Prime Minister Christopher Luxon has made no secret of New Zealand's interest in the lower level of the nuclear-powered submarine pact AUKUS - but won't ask the only invited country outside of the triad about it.

Luxon leaves for Tokyo on Sunday morning for a three-day Japan flash-in-the-pan visit with dual business and political purposes.

A key focus will be security. Japan is a strategic powerhouse and is a vocal critic of China's increasingly provocative moves in the Indo-Pacific. And outside of the three partners of the AUKUS alliance - Australia, the United Kingdom and the United States - Japan is the only country to have been invited to join pillar 2 which seeks to share advanced technology.

The New Zealand Government has been exploring what joining pillar 2 would mean which has agitated China - it was raised during Premier Li Qiang's meeting with Luxon in Wellington this week and China's Ambassador to New Zealand has said joining would be akin to "taking sides".

But despite New Zealand's curiosity about the deal, Luxon said he didn't expect to discuss AUKUS.

 "If you're sitting in Japan, you've got a lot of countries wanting to do information-sharing agreements with you."

"I don't think it will come up in a bilateral sense, per se. I mean we know that they're interested and have been invited on pillar 2 - I think is the first entry to pillar 2," he said.

"Again, our issue is really just working with the three member countries at this point and their officials to ascertain what the opportunity is for New Zealand.

"I think they're almost mutually exclusive in some ways - I'm sure they'll be alluded to on some level - but we're not talking to the Japanese about our pillar 2 exploration that we've got going on."

New Zealand is already in talks with Japan on another strategic arrangement to share information better between the two countries. The deal was signed when former Prime Minister Jacinda Ardern visited Japan in 2022 and could see information classified as 'top secret' exchanged.

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Japan has similar agreements with other Five Eyes members and has been viewed by some commentators as spade-work for it joining the intelligence partnership of English-speaking powers.

But two years later, negotiations are still ongoing despite a promise to speed things up last year.

"We want to see that there's progress on that. As to whether it's completely signed off for this visit or not, I'm not a hundred percent sure on that just yet," said Luxon.

"If you're sitting in Japan, you've got a lot of countries wanting to do information-sharing agreements with you."

When the two leaders meet next week, Prime Minister of Japan Fumio Kishida will have just returned from the powerful G7 summit where he led a session on China's growing military assertiveness in the Pacific. Japan has also been readying new sanctions against Chinese companies for providing materials that can be used for military purposes to Russia.

Former New Zealand Ambassador to the Republic of Korea, Philip Turner, wrote this week on Asia New Zealand that he expected the intelligence deal and AUKUS could have been a sticking point with Premier Li.

Luxon said it wasn't.

"That hasn't been one of the conversations with the Chinese at all. We never discussed Japan."

However, Luxon is keen to discuss trade opportunities to help reach his goal of doubling exports.

The business class section of the NZDF 757 will be loaded with about 30 business chairs and chief executives - including Dame Therese Walsh ("she's a really good friend") and the newly knighted Sir Peter Beck ("a good mate as well").

On his last major trip overseas to the Philippines, Luxon was told by a member of his business delegation to stop saying on the world stage that New Zealand was "open for business" as it was unhelpful.

Luxon - though - is sticking to his line.

 "That hasn't been one of the conversations with the Chinese at all. We never discussed Japan."

"We've got a bit of work to catch up on and to sort of reannounce ourselves to Japan - as we have to the rest of the world - and that we're open for business," Luxon said.

Luxon said New Zealand had been slow out of the blocks after COVID-19 and is eager to turn around slowing Japanese tourism numbers. He wants Japan to see us as both the land of milk and honey, and of opportunity.

"The Japanese think of us as a small country at the end of the world, that it's lovely with some nice smiley people and some lots of cows. And the upshot is that we are wanting them to think of us in a different lens."

That's where Sir Peter comes in - Luxon wants to shoot for the stars. Japan this year established a multi-billion-dollar Space Strategic Fund which presents an opportunity for New Zealand's growing space sector.

"Here's an example of how you could build out another string to the New Zealand core of music that we play economically by introducing a smarter, higher-value sector over time."