The Defence Force is investigating claims Iranian missiles have hit a base at Taji, Iraq, where Kiwi troops are based, a Defence Force spokesman has confirmed.

Intelligence organisation DWS claimed Iranian missiles struck Taji on Wednesday afternoon.

The claims came soon after Minister of Defence Ron Mark said he was worried about increased Middle East tensions as the fate of Kiwi troops in Iraq comes under intense scrutiny.

But Mark on Wednesday said he had "absolute confidence" in Defence Force leadership, as reports emerged Iran had fired ballistic missiles at two US bases in Iraq. 

Forty-five Defence Force personnel were thought to be in the Taji​ military complex near Baghdad and another five in the Iraqi capital itself.

Since Iranian Quds force leader Qasem Soleimani was killed in a US drone strike, Iraq's parliament voted in a non-binding resolution to expel US and allied forces.

"The Iraqi government has not asked us to withdraw," Mark said.

"We have a mandate for a mission."

Mark said he had faith in the ability of New Zealand's coalition partners to assess the situation on the ground and it was not for him to interfere in operational matters.

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The Defence Force put its training activities in Iraq on hold after Soleimani's death.

And Mark on Wednesday told media: "Yes, we are concerned."

Mark said the New Zealand Government wanted calm, de-escalation and dialogue to resolve regional tensions.

Mark on Wednesday said New Zealand was talking to its international coalition partners and "situational awareness" was pivotal as the US-Iran relationship deteriorated.

Economist David Butcher, who'd previously visited Iran and Iraq, said any impact on New Zealand's economy would depend on the intensity of conflict.

"Once shooting wars start, anything can happen."

But he said the US was probably no longer as dependent on importing Middle Eastern oil as it had been a few years ago, thanks to a boom in its domestic shale oil sector.

Butcher said in the 1980s Iran-Iraq war, "New Zealand was successfully selling meat to both sides".

The Ministry of Foreign Affairs and Trade said on its website the security situation in the Middle East was "unpredictable and may become increasingly volatile".

"The security situation could deteriorate with little to no warning. New Zealanders in the Middle East region are advised to avoid any demonstrations, marches, processions, and keep away from military sites."