Mr Key came under fresh questioning about the deployment after Isis' takeover of Ramadi brought them within 80km of the Taji base where the 140 Kiwis are stationed alongside Australian troops. That prompted warnings Isis will target Taji either with missiles or by disrupting supply lines.
Asked if New Zealand troops would evacuate the base or stay and fight if it was attacked Mr Key said there were a number of trigger points for an exit strategy.
"It's about whether we believe the safety and security of our people are compromised. If they are and we see a number of trigger points that reach that point, then we'll get them out. None of those have been triggered and at this point there's no likelihood they'll be triggered."
He said Taji was the safest place for the troops to be and if he had a visit scheduled for next week he would still go.
Despite Mr Key's claims, security expert Paul Buchanan said Taji was likely to be a "major target" for Isis over the next few months.
Writing on his 36th-parallel.com website, he said if Isis gained control of land supply lines between Baghdad and the base it would leave the allied forces reliant on air supply or fighting their way out.
"If that happens it is doubtful that the NZDF troops will hunker down 'behind the wire' and do nothing else."
Speaking on ABC, Australian counter-insurgency expert David Kilcullen also warned the proximity to Taji could put the troops in danger and Isis manoeuvrings threatened to cut it off from other bases.
NZ forces
• 140 personnel at Taji base.
• Isis takeover of Ramadi has brought them with 80km of the base.
• There are fears Isis will attack Taji.