Military analysts for a Swedish publication rated New Zealand one of the hardest countries in the world to invade. But "there are many subtle ways of attacking a country that fall short of military means", a security expert warns.

The article in the SvD Perfect Guide doesn't appear to be an in depth look at the issue. Other countries mentioned as being hard to invade include Switzerland, Australia, Iceland and Russia - which has actually been invaded quite a few times.

That said, the article is probably accurate about New Zealand. We're a long way from most countries and  lack, at least as far as we know, anything of huge value. The country is also of limited strategic importance, except maybe as a staging post to the Southern Ocean and Antarctica 

The Global Peace Index ranks New Zealand as the second-most peaceful country in the world - behind Iceland and ahead of Portugal - taking into account societal safety and security, ongoing domestic and international conflict and the level of militarisation.

Dr Paul Buchanan, director of 36th Parallel Assessments, said a ground assault on New Zealand would be a formidable undertaking and he doubted very much one would be launched. 

"But we have a very small military ... We're not like the Cubans or the Swiss  who have neighbourhood militias - the Swiss are armed to the teeth. Common citizens can take up arms and make the cost of invading much higher," Buchanan said.

"I don't know if the New Zealand citizenry is up to it, specially the millennials, I don't think they're of a mindset to shed blood in defence of the homeland."

In any case, an assault on New Zealand was likely to be mostly cyber, which would be effective in making people compliant.

"The first thing you're going to face is a massive cyber attack that will deny your military the ability to defend themselves."

The power grid could also be shut down, and government communications interrupted.

New Zealand was a classic case of a place that could be encircled and have its supply lines cut off. "Just have a maritime and air blockade and strangle us, and we would have to give in," Buchanan said.

"There are many subtle ways of attacking a country that fall short of military means," he said. 

"If you are planting false narratives in the media and promoting a certain point of view that could be hostile to traditional values, and friendly to new emerging powers ... trying to disrupt traditional ties that bind say New Zealand, Australia and the US," Buchanan said.

"The motive would be to replace them with a narrative sympathetic to other powers. The Chinese always come up in these discussions, but they aren't the only ones. A lot of actors are playing the influence game."

Buchanan raised the possibility New Zealand could get sucked into a dispute over the South China Sea.

"I'm beginning to think we will eventually see a hot war there; maybe small but someone's going to start shooting at someone. That's going to drag in a lot of other players."

Latest developments from that area, as reported in the Sydney Morning Herald, include China landing heavy bombers on an island in the South China Sea, and installing anti-ship and anti-aircraft cruise missiles on some islands.

That's despite other countries in the region claiming the islands, and negotiations supposedly under way to prevent such escalation.

If New Zealand were to get sucked into a hot war in the South China Sea, the Chinese could go after targets in this country such as listening posts for the Five Eyes intelligence alliance, Buchanan said.

"That's in the realm of the possible. You wouldn't have to invade to make the point we should stay out."