The Iraqi Government might have invited New Zealand troops to train its army but it still has not given authority for them to shoot to kill if they do go.
Under the rules of engagement, foreign troops have to have authority to shoot to kill, or otherwise face the possibility of prosecution in Iraq.
Prime Minister John Key said, if soldiers went, a protection force would go with them to ensure their safety.
But Mr Key said what legal authority they would have to defend themselves had not yet been agreed.
"That's a matter that we need to resolve and it's a matter that I'm confident we can resolve.
"So obviously we wouldn't send our people unless we're confident that they can undertake whatever actions are required and do so lawfully. So we're working our way through that," Mr Key said.
The Labour Party's foreign affairs spokesperson David Shearer said it was likely to be a problem if New Zealand troops went.
"The latest state of forces agreement that was signed was done with the Americans in 2009 and that was to take the Americans out. The Iraqis don't want to have more foreign troops in there.
"[The Iraqi Foreign Minister Ibrahim] al-Ja'afari said to me we've got enough men and enough courage. We need air support, air strikes and intelligence and signals."
Mr Shearer said the question of how foreign forces should be allowed to defend themselves had been raised in the case of Australia.
"What has happened with the Australians is that they've brought in forces to protect their trainers but ... their SAS has come in in diplomatic passports because they don't want to have a state of forces agreement that would show that they are bringing back again foreign troops and that is an anathema to the Iraqis. They don't want it," he said.
The Labour Party leader Andrew Little said if the Government sent a New Zealand training force to Iraq it should be able to defend itself.
But he said Mr al-Ja'afair made it clear last week the Iraqis would prefer other help.
"The foreign minister was very clear. There are a range of things they want or would like to have. It is not just about military assistance. There's the reconstruction and humanitarian assistance they want and I think we should be focusing on that."
Mr Little said Labour continued to oppose sending troops to Iraq, whatever their role.
But Mr Key said New Zealand had a contribution to make.
"It's not a matter of just waving the flag. It's ultimately about stopping ISIL [Islamic State] and forcing them back.
"And I think if you look at the actions of, you know, a number of countries over recent months I think you can claim that they are being successful. They are certainly not getting the easy ride they were getting some time ago but there up to 60 nations playing some part."
Mr Key said Iraq had asked New Zealand to send troops to help train its army and the Cabinet would decide on that on Monday.