Mercy Corps, an aid and disaster response charity which has its headquarters in Edinburgh, also said the scale of the humanitarian crisis in Syria is huge but has been almost forgotten as the focus has shifted to the Islamic State (IS) advance and in Iraq.
It has called on international intervention to bolster humanitarian aid as the Islamic militants continue the violent jihad against Shi'ite Muslims across the region.
Mercy Corps is helping about 2.5 million people affected by the Syria crisis, including over 1.7 million inside Syria and almost 700,000 refugees now living in neighbouring countries including Jordan, Iraq, Lebanon and Turkey.
Helping refugees is hindered by parents hiding their daughters for fear they will be snatched and sold while conditions vary, with most refugees in Turkey sheltering in derelict buildings while others are hiding in the border hills between Syria and Lebanon.
IS have also attacked refugee camps in Lebanon, killing 20 people including two babies in one in the Bekaa Valley last week.
Rae McGrath, Mercy Corps Middle East director, has appealed for a longer term strategy to halt atrocities against populations caught up in conflict.
He said: "For me the issue is, first, generally in relation to Syria is to just understand the scale of the suffering there. I have done this work for 30 years and have never experienced anything so sustained and awful that ordinary people are having to deal with.
"It is really important to understand the complexities that we are dealing with along with the Syrians. What is going on in Iraq is terrible. But we are seeing the almost complete abandonment of Syria as an issue and shift to Iraq.
"The world has wanted to respond to Syria but has not really been sure how to respond and yet at the same time Non-Governmental Organisations like Mercy Corps have really been working right at the coalface in a way that we probably have not been called on to do in a number of years because of the intensity and fast-moving nature of the conflict.
Mr McGrath was a founder member of the International Campaign to Ban Landmines, delivering the Nobel Lecture when it was awarded the 1997 Nobel Peace Prize.
The appeal comes as concern grows for the stability of the region and the impact on the UK as a video of the murder of US journalist James Foley appeared to show the beheading being carried out by a man with a British accent. It is thought up to 500 British citizens have joined the jihad.