"The Australians have got a different system to us. Their national security committee can authorise the military to do all sorts of things, which they have done, with regards to training and preparations for missions. What finally happens with them, is the cabinet makes the decision on the deployment.
"In New Zealand it's the other way around - the Cabinet makes the decision to deploy. And we announced that back in February."
The deployment would be a staged one, he said.
"The reality is - I don't want to have a dispute with Mr Abbott - but there is a staged entry into the Taji airbase, you can't just all turn up on one day and expect everything to be in place.
"That is going to take place to a point where the whole mission will be up and running by the end of May. There's nothing changed in that."
However, he admitted that "sometimes they [NZDF] probably could tell us a little bit more at times about their preparations".
"In the end, I've got huge respect for these people, they're going into a difficult job, they're doing it willingly and you've got to let them have operational movement," he said.
"You can't sort of say, 'I want to know when all the packs are packed and the motor's running etc', you've just got to let them go ahead and professionally put together this mission with the maximum safety possibilities for our soldiers in mind, and that's what they do."
Mr Brownlee also stuck to the original announcement that New Zealand troops would only be in Iraq for two years.
"That's our mandate at the moment, and I can't see why we would change that," he said.
He added: "Remember we're not going there to win the war, I think that's one of the important things here, that the Iraqi government, and most of the Middle Eastern countries that we associate with, have said, 'this is our fight, we need help training our trainers to train others'. And that's the effort that we're going to be putting in."