New Zealand Defence Force troops based in Iraq are at risk of being caught up in Iran's retaliation over the US killing of top general Qasem Soleimani, a senior Waikato University academic says.

Photo: New Zealand Defence Force

Today Iran has announced it will roll back its commitments to the 2015 nuclear accord amid heightened tensions over the assassination of Soleimani at Baghdad Airport last Friday. The killing was ordered by US President Donald Trump.

As well, Iraqi MPs have voted in favour of all foreign military leaving their country.

New Zealand has up to 45 military personnel in a non-combat training role at Taji Military Complex in Iraq, and had already planned to withdraw all troops by June this year.

Foreign Minister Winston Peters said heightened tensions in the Middle East are of strong concern, and government is calling for restraint and de-escalation.

Peters said achievements in the fight against Islamic State have been hard won, and it's important those gains are consolidated, not undermined.

The government will keep the security situation under close review, and any threats to deployed personnel and diplomatic staff are viewed very seriously.

However, it has not yet commented on whether it will abide by the Iraqi government request to withdraw all foreign troops.

Photo: RNZ / Dom Thomas

National's Defence spokesperson Mark Mitchell said there is still a threat from groups like al-Qaeda and Islamic State so it would be wise for the government to see if the Iraqi government acted on the resolution or whether the need for global security would prevail.

He said New Zealand should not make a knee-jerk response.

"The coalition and Iraqi troops have been very successful in dismantling and removing the threat of ISIS and the caliphate," Mitchell said.

"I've always felt very strongly the important part is the follow up, and this is often where we get the strategy wrong - leaving too early, the vacuum reappears and then all of a sudden we're back in a situation where international terror and global security is a bigger issue for us again."

However, the government may have no choice but to bring forward the June departure announced by Prime Minister Jacinda Ardern last year.

"Of course we're there at the invitation of a sovereign nation, Iraq, and if their Parliament decides that they no longer want coalition troops in their country supporting training, participating and ensuring that that threat does not return, then, of course, we'd have to respect that," Mitchell said.

Alexander Gillespie, who is a professor of International Relations at Waikato University, told Summer Times the government may decide to accelerate the Defence Force's exit from Iraq.

"I'm concerned about their safety. I think this could turn quickly. It will depend on what Iran does next and they have a menu of options of what they can do.

"They're going to try and avoid a direct conflict [with the US] because they won't win a direct conflict but indirect conflict they've got a much better chance and one of the vulnerable points is Iraq because there's a lot of Shia militia there and the country doesn't have a strong central authority.

"It's also got woeful economic conditions... so it's ripe for turmoil so if they decide to pressure and focus on the coalition troops, including the New Zealand coalition troops, they could find themselves at the short end of the conflict."

Photo: AFP

He said New Zealand troops went to Iraq as part of a US-led coalition, not as part of a United Nations presence. If Iran chose to make trouble it could even try and cause a civil war in Iraq and the coalition troops could become a target.

"The worst-case scenario you'd want to happen now is that the Iranian Shia militia in Iraq decide to start attacking those troops because if that happened we would not want to be part of that war.

"It was right to be there to defeat Islamic State; it's not right to be there if Iraq fragments in a regional war with Iran."

Gillespie said the US has been acting on its own right now, because it knows traditional core allies like France, Germany and likely New Zealand would not have been in favour of the killing of Soleimani.

International law was divided over such extra-judicial killings, but on a practical level it meant nations lost the ability to keep talking to each other.

"This is an extreme act. This is the kind of act that [George] Bush and [Barack] Obama both steered away from even though it would have been possible.

"But as a provocation many countries when they have one of their heads of state or one of their senior diplomats or ambassadors killed will see this traditionally as a cause for war and a legitimate cause for war."

Photo: Mohammed SAWAF / AFP

Nuclear programme will be speedily re-activated - Gillespie

He believes Iran will now be trying to accelerate its nuclear programme, and at the time it signed the 2015 nuclear deal, it was probably 18 months away from having a nuclear bomb.

Gillespie said either the US or Israel would act if Iran achieved nuclear weapons, because neither country would tolerate such a threat for its citizens.

MFAT is advising New Zealanders not to travel to Iraq because of the fears of violence and terrorism. Fifteen New Zealanders are registered as being in Iraq and they are advised to leave.

Pacifist group seeks NZ troops' immediate withdrawal

An Auckland pacifist group is calling for New Zealand Defence Force troops to leave Iraq and for the NZDF to reduce its ties with the United States.

Auckland Peace Action said the US has wanted war with Iran for decades, and our government must resist any involvement in further conflict, including refusing to provide intelligence or personnel.

Spokesperson Valerie Morse said the Defence Force must respect the Iraqi parliament's wish for all foreign troops to return home.

The assassination of Soleimani was Trump's most brazen attempt to provoke Iran, she said, and the New Zealand government should refuse any support for a new war.