The UN says more than 1.1 million people - nearly one out of 30 - in Iraq are now displaced.
Save the Children says although spared the heaviest force of violence from ISIS fighters, the area is already dealing with an influx of refugees from neighbouring Syria.
"We have already been responding to the Anbar crisis and Syria crisis…but we keep seeing new numbers of people fleeing from the area so it’s not a stable situation," said Karl Schembri of Save the Children, who is working in Erbil.
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The city is the largest in the Kurdistan region and has seen 100,000 of about half a million displaced Iraqis from Mosul.
Mr Schembri says aid agencies are struggling to cope with the numbers of displaced people.
"The situation is one of chaos and confusion for the hundreds of thousands of Iraqis, who are forced to flee from their home…they are confused, they don’t for how long this is going to go on.
He says a number of families and children are now living on the streets after their savings ran out.
"I met families yesterday who were living in a park because they couldn’t afford to stay anywhere else. So there is a massive amount of people displaced already but also an increasing a number families and children who are becoming vulnerable the longer this conflict takes."
Full interview with Karl Schembri
The more than 1 million displaced Iraqis join a growing tide of refugees worldwide.The UN says the global number of asylum seekers and displaced people has now surpassed 50 million, the highest figure since World War Two.
The agency's Global Trends Report says conflicts in places such as Syria, South Sudan and the Central African Republic have led to 6 million more people than last year becoming refugees.
