No Kiwi withdrawal from Iraq, even as Isis advances - John Key

New Zealand soldiers will not be withdrawn from Iraq even if the Islamic State reaches Baghdad, Prime Minister John Key says, after huge gains by the extremist group brought the conflict closer to the capital.

Mr Key said the Islamic State's advance was not a "trigger point" for reviewing New Zealand's non-combat deployment.

The city of Ramadi, 130km from Baghdad, fell to Islamic State (Isis) forces on Sunday, effectively giving the caliphate power over a third of the country.

New Zealand is based at Camp Taji, around 30km from Baghdad and an hour's drive from Ramadi.

Asked whether troops would be withdrawn if Isis neared Baghdad, Mr Key said: "That's not the trigger point, I don't think. There are other potential trigger points, but that's not really one of them.

"There isn't a particular thing that says on this day we will review it and on this day we won't. We constantly assess. We won't take ridiculous risks but just because Ramadi has been taken by Isil doesn't mean our guys should come home."

The Prime Minister reiterated at his weekly press conference today that New Zealand troops were in the "safest place they can be within Iraq".

The massive Taji base, where some American troops are also based, was chosen after research trips by Defence Force officials.

"In the end, the security of our soldiers is paramount," Mr Key said. "That's why there are so many protection people, that's why we were so cautious about where they went and that's why we researched what we did for such a long period of time."

Out of the 106 soldiers based at Taji, just 16 were military trainers and most of the remainder were made up force protection. The Defence Force has previously confirmed that all of the soldiers were armed and retained the right to self-defence.

The Isis victory in Ramadi raised questions about the capability of the Iraqi military, as many soldiers abandoned their posts and armoured vehicles, some of which had been provided by the US military.

Mr Key said the extremist group's advance in Iraq's northwest underlined the difficulties the country was facing.

He said it also showed the importance of New Zealand's training of Iraqi forces, "because in the end if Iraq is going to get control of its cities, Mosul being the largest and most obvious, and now Ramadi, it's going to need its forces to stand up and take that back to Isil".