War with Iran 'now more likely than not' - expert

An international law expert fears war is "now more likely than not", following Iran's seizure of a British-flagged oil tanker.

And New Zealand might be asked to help out.

The oil-tanker Stena Impero had 23 crew on board, and all eyes are on the US and Britain's next move.

Professor Alexander Gillespie, international law expert at the University of Waikato, says US President Donald Trump is openly calling for a multinational effort - and we will be on the list.

"Australia also will be asked - it's more likely that Australia would say yes. For a country like New Zealand, we'd have to weigh the matter very carefully," he told Newshub.

Gillespie believes war is more likely than not, with Iran's "provocative" actions having the potential to trigger a direct response from Western powers.

"It wouldn't be of a global threat level, in terms of security of the planet. 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 boots have to be involved... it could another Syria or Afghanistan."

Revolutionary Guard troops storm the Stena Impero.
Revolutionary Guard troops storm the Stena Impero. Photo credit: Reuters

He suspects New Zealand has already been invited to join a US-led coalition to safeguard waters around Iran.

"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."

UK Foriegn Secretary and potential future Prime Minister Jeremy Hunt has urged Iran to release the vessel, which Iran says collided with a fishing boat.