(CNN) -- Camps housing Sri Lankans displaced this year by fighting between the government and Tamil Tiger rebels are seriously overcrowded and at risk with the coming monsoon season, a British charity director said Friday.
Tamil civilians, pictured in May, stand behind a barbed-wire fence at a refugee camp near the northern Sri Lankan town of Vavuniya.
Twice as many people than originally intended are now housed at the camps, said Geoff O'Donoghue, the director for the international division of the Catholic Fund for Relief and Development.
He returned this week from a week-long trip to Sri Lanka, where he said life is extremely difficult for camp residents.
The Sri Lankan government earlier this week reacted harshly to comments by another charity official critical of the suffering of children at the camps and in the conflict.
The government accused a U.N. Children's Fund spokesman, James Elder, of spreading untruths and propaganda from the Tamil rebels, revoked his visa and told UNICEF that he must leave the country by September 21.
O'Donoghue said he and two English bishops drove around the displacement camps for a week and were able to meet with a Sri Lankan brigadier who is in charge of operations there.
"The conditions in the camps (were) seriously overcrowded," O'Donoghue told CNN. "The government had anticipated originally 150,000 people, and in the end received closer to 300,000."
The brigadier told him the government is "inundated" with people. Watch Sri Lanka's human rights secretary speak on the issue »
Heavy rainfall recently flooded one area of the camp and destroyed homes there, causing people who already had very little after the conflict to lose all they had, O'Donoghue said.
The monsoon rains will only worsen the situation, he said, causing flooding of latrines, which will bring fecal matter to the surface and put people at risk of waterborne disease. For a while, there was an average of 40 people per latrine, while the U.N. standard is about 20, O'Donoghue said.
Around the camps, people are living in a variety of shelters including canvas tents, plastic sheeting, or sheds made of corrugated metal. About two meters (six feet) separates each shelter, he said.
"The people living inside these are every aspect of the population that you can imagine -- young, old, men, women," he said. "It's a whole community that's been displaced from the north into the camps."
UNICEF Executive Director Ann Veneman said the agency is "extremely concerned and disappointed" by Sri Lanka's decision to expel its spokesman, Elder, and U.N. Secretary-General Ban Ki-moon strongly denounced the move.
The United Nations said Ban expressed "full confidence in the work of the United Nations in Sri Lanka, which includes making public statements when necessary in an effort to save lives and prevent grave humanitarian problems."
He also promised to take up the issue with Sri Lankan President Mahinda Rajapaksa at the earliest opportunity.
UNICEF fiercely denies that Elder was voicing Tamil propaganda.
"Through Mr. Elder, UNICEF has consistently spoken out against the suffering of children on both sides of the intense hostilities earlier this year and called for their protection. UNICEF unequivocally rejects any allegation of bias," Veneman said in a statement issued this week.
"Mr. Elder's role for UNICEF was to reflect how the conflict gravely impacted upon children," said Sarah Crowe, the agency's spokeswoman for South Asia. "He did this based on concrete information that the United Nations attained and verified."
Elder isn't the first member of an aid agency that Sri Lanka has pushed out of the country, but it is rare to expel a U.N. employee.
"Mr. Elder expressed public views contrary to his mandate as a U.N. official and in a manner that was embarrassing to the whole government," said Palitha Kohona, Sri Lanka's foreign affairs secretary. "Sri Lanka is a member of the United Nations and it is not in any way subject to the judgment of U.N. officials."
O'Donoghue said the Sri Lankan government sees the problems in the displacement camps as a matter of urgency, but for now they aren't letting residents move out.
"Their solution may not be to get people out, but to improve the camps and to extend them," he said.
The government says it continues to hold people in the camps because it feels it is unsafe for them to return home, given the extensive landmines buried across the landscape. The government is also still screening the displaced people to filter out any former Tamil Tiger combatants, O'Donoghue said.
By contrast, aid agencies are focusing on resettling people to places outside the camps, he said.
As an example, the Catholic Church has offered to take 12,000 people from one district and move them to a local shrine that already has 600 latrines, because the shrine accommodates pilgrims.
The government is considering the idea seriously, O'Donoghue said.
"But it's very slow, and I think the church, the non-governmental organizations, (and) the international community are right to insist that the real solution to this problem is the resettlement of this community back in the places where they came from," he said.
The Sri Lankan military defeated the Tamil Tigers earlier this year, ending a conflict that began in 1983. The rebels -- formally known as the Liberation Tigers of Tamil Eelam -- were waging war for an independent state for minority Tamils in Sri Lanka. As many as 70,000 people were killed in the conflict.