Up to 20 refugees are dying each day on the Kosovo-Macedonia border where more than 60,000 people are stuck "in no-man's-land" between the two countries, according to UNICEF Ireland.
The aid agency said the plight of these refugees who have been refused access to Macedonia is the most desperate.
"Most of the refugees are exhausted after their ordeal, bewildered and traumatised by recent events in Kosovo and their forcible deportation. The incidence of diarrhoea-diseases has increased and there are no sanitation facilities. Due to the rain, the field where these people are located has turned into a mud-bath."
The agency is currently distributing relief supplies and setting up a system aimed at reuniting the 150 unaccompanied children identified in the group with their parents.
Meanwhile, Goal has announced it is to deliver a 20-tonne load of relief goods this weekend to its programme on the Albanian border with Kosovo. In addition, two logisticians and a nurse midwife will fly to Tirana this evening to join Goal's relief team.
A Refugee Trust Ireland aid team will return tomorrow to Montenegro, where it is helping to establish a safe water system, provide temporary shelter and offer psychological support to refugees.
Up to 15,000 people have flooded into the coastal town of Ulcinj where, it said, "there is no sanitation, washing facilities, no kitchen facilities, no medicine, no healthcare. Pharmacies have run out of drugs. The water system is under strain. People have been living on bread for the past week".
The agency warned "the pressure on the Montenegro government is unsustainable" and without assistance the country would collapse.
World Vision Ireland said it completed another delivery of emergency supplies to Rozedaja in Montenegro last weekend.