They had gone about it in a fairly systematic and cautious way.
They were getting assistance from other countries in the training of their troops, battle planning, strategic positioning and air cover.
"But I stress again, it is the Iraqis who are doing it, not anyone else."
The meeting is the third Iraq-focused planning meeting Brownlee has attended this year.
The first was in Brussels in January, followed by another in Stuttgart in Germany three months later.
New Zealand and Australia forces are helping to train Iraqi forces at Camp Taji near Baghdad.
Up to 40 per cent of Iraq had been in ISIS hands and that is now about 10 per cent.
Ramadi and Fallujah have been retaken with Mosul the next likely target.
Brownlee said the meeting was not to plan the next target but looked more at what needed to be done once territory was won back, including the need for policing.
"Increasingly it is moving into strengthening of civil governance of those communities and alongside reconstruction of those communities as well."
He compared it to the challenge of rebuilding Christchurch after its devastating earthquakes.
"The damage is big. I just look at from the perspective of knowing how hard it is when you are dealing with the loss of civil infrastructure and we've seen it in a way in Christchurch where there was no intention around it.
It takes time, it takes effort and it take commitment. The strong focus on that is extremely encouraging."
US Defense Secretary Ash Carter hosted the meeting, which was also attended by Iraqi Defence Minister Khalid al-Obeidi.
Foreign Minister joined the Defence Ministers the next day, although Brownlee deputized for Murray McCully.