New Zealand's armed forces face an increasingly dangerous world and will need to get more assertive and sophisticated.

That's what the first Defence Assessment in seven years has warned, and it pulled no punches in its opening line.

"New Zealand's strategic environment is deteriorating, and security threats are increasing," the Ministry of Defence report said.

It's not just major power rivalries or established threats - a "grey zone" between war and peace will seriously test New Zealand, the paper said.

The grey zone was the domain of sabotage, propaganda, and foreign interference, the paper added.

The long-held pattern of New Zealand responding to natural disasters or minor regional conflicts is a thing of the past, the assessment added.

Instead, Kiwis can expect to be called on to provide "more sophisticated military capabilities" in support of regional partners.

The Ministry of Defence said strategic competition and climate change, especially in the South Pacific and Antarctica, had direct implications for New Zealand's safety and security.

The paper released this afternoon said US-China rivalry was a major driver of strategic competition.

And the Defence Assessment said even if the contest between major powers did not degenerate into open warfare, it would play out in space, cyberspace, and other arenas.

"China's rise is the major driver for this competition," the assessment summary added.

But the assessment also pointed to violent extremism, global organised crime, and "the weaponisation of information and emerging technologies" as significant threats.

Increasing nationalism in some places, and Russia's undermining of the global rules-based system, were destabilising global order and subsequently were a threat to New Zealand, the paper added.

The ministry said an approach developed for the more benign world of recent history cannot be relied on to defend New Zealand in the near future.

Mirroring much recent geopolitical language out of America, the report quickly named the "Indo-Pacific" as the arena most likely to destabilise global affairs and New Zealand's security.

The paper pointed out that the US was returning to a more engaged role.

"United States engagement and presence across the globe, enabled by its expansive portfolio of bilateral and multilateral security arrangements, has underpinned stability and security in key global regions."

The assessment was released under embargo. Minister of Defence Peeni Henare will shortly address media.