International relations experts are split on whether the standoff in the Middle East will result in war.
Iran has seized a British vessel in the Strait of Hormuz, possibly in retaliation for the UK's detention of an Iranian oil tanker earlier this month.
Tehran said it was violating international maritime rules, sailing in the wrong direction, and had collided with a fishing boat.
The tension comes as the US has been tightening sanctions on the Middle Eastern power, which has resumed enriching uranium it swears is for peaceful energy generation, but the West suspects is part of a nuclear weapons programme.
University of Auckland international relations expert Prof Stephen Hoadley told The AM Show on Monday Iran isn't trying to pick a fight.
"Some people say it's signalling - the Iranians are signalling to the Brits and to the Europeans, help us out - provide the financial instruments so we can continue trading with oil, or suffer the consequences," he told host Duncan Garner.
"They want to be able to trade their oil. The Europeans are working towards that end, to evade the US sanctions. Maybe this is a signal that the Iranians do have cards to play - and those cards are to harass British shipping."
He says the "highly provocative" strategy isn't likely to work, however.
"It's going to show the Iranians are bloody-minded, they're difficult to deal with, unpredictable, not following international law. I don't think it's going to do them any good."
But he doesn't expect the standoff to end in war.
"Nobody wants war - the Iranian people don't want war, the US people don't want war... I don't think it will get to that point. I'd like to assure viewers there's not going to be a nuclear war because the Iranians don't have nuclear weapons - yet. In a year or two, perhaps they will."
Hoadley's view is at odds with University of Waikato international law expert Prof Alexander Gillespie. He told Newshub at the weekend war is "more likely than not", and it's likely New Zealand would have already been approached by the US to help out - at least in a support role.
"Britain and America will likely see this as a clearly illegal action against the freedom of navigation, and hostage-taking. Moreover, if they don't step in now, the chances are it will get worse.
"Trump, also, is not a man known for turning the other cheek. The fact that the Iranians now have a number of hostages will not deter a military strike."
He agrees with Hoadley that any war wouldn't be a global threat though.
"But if there was a regional conflict, it could still be quite bloody. Best-case scenario, it would be on the water... Worst-case scenario it involves intrusion onto the land, and boots have to be involved."
If that happens, Gillespie says to expect a drawn-out conflict like those seen in Syria and Afghanistan.
The UK will have a new Prime Minister later this week, likely to be gaffe-prone Boris Johnson.