He lied:
The Government will not send combat troops to Iraq to fight Islamic State (IS) but has sent military staff to determine whether New Zealand will train Iraqi troops, John Key has announced.
[...]
Ten military planners - three whom left for Iraq yesterday - would gather information from allied bases in the region and report back to ministers on whether New Zealand should have a role training Iraqi troops to fight the jihadists.
NZ troops don't get deployed without a government decision to do so. Which means that Key lied directly to Parliament on one of the most important matters he could have. And in doing so, he lied to us about whether he had involved us in a foreign war, and by doing so, significantly increased the risks to ordinary New Zealanders.
This is the contempt our monarchical Prime Minister has for us: he doesn't even think he has to be honest about involving us in a war. And its why we need legislation prohibiting the deployment of NZ troops overseas without explicit Parliamentary approval.