The United Nations chief ordered April 24 a team to assess the "rapidly deteriorating situation" in Sri Lanka as tens of thousands of people fleeing the war zone included civilians with untreated wounds.
Some 170,000 to 180,000 civilians now live in government camps, according to the U.N. spokesman in Colombo.
An additional 15,000 to 20,000 civilians remain trapped in the coastal strip measuring just five square miles still controlled by the Tamil Tigers.
Reporters have also been denied access to the area.
Both the rebels and government deny targeting civilians, but the U.N. estimated that more than 4,500 have been killed in the past three months. The Red Cross has said it has evacuated 6,000 wounded civilians since January.
Doctors Without Borders said a rapidly growing number of badly wounded civilians have been arriving at a hospital near the war zone in the past few days.
"Our hospital has got about 450 beds, and we've now got more than 1,700 patients in the hospital – on the floor, in the corridors, and even outside." Dr. Paul McMaster said in an interview released by the Switzerland-based aid group.
Speaking in Brussels U.N. Secretary-General Ban Ki-moon stated he would immediately send a team of experts to monitor the situation and "try to do whatever we can to protect the civilian population."
The U.N. Security Council has asked the Tamil Tigers to lay down their arms and join peace talks.
The U.N. further urged the government to give international aid agencies access to those affected by the fighting. Since September, only the International Committee of the Red Cross has had access, and only two ill-equipped hospitals function in the war zone.
"Sometimes we're operating on both the mother and father and a child from the same family that had been wounded in the same explosion or mine. We're seeing whole families that are wounded," McMaster stated.
This week's exodus began Monday when the military broke through a key rebel bunker on the northeastern coast, releasing a flow of fleeing civilians.