But the ICRC, like the United Nations and other aid agencies, complained that the Sri Lankan government denied it access to the war zone during the final weeks of the conflict.
The other agencies also have had problems reaching camps since the war ended, the Canadian Press said.
Kellenberger called Wednesday for greater humanitarian support for the 300,000 displaced Tamils.
"The direct humanitarian consequences of the conflict are immense. We have to increase aid," he said, adding that he was especially concerned about medical assistance.
"Access that the Sri Lankan government has granted is still not clear," Kellenberger said, adding that discussions are continuing between the ICRC and the Sri Lankan authorities.
"Just now, what's still not clear is to what extent the government of Sri Lanka will really make it possible for us to carry out the tasks we find important," the ICRC chief said. "But we are in discussion with them."
“We would like to visit all these camps to check if the conditions are right, in order to see if the treatment is right, and in order to allow those in the camps to be in touch with their family members,” Kellenberger said.
Sri Lanka's president Mahinda Rajapakse on Sunday rejected a call by the UN Secretary General Ban Ki-Moon, who visited the least squalid of the campa, Manik Farm, to lift restrictions on aid delivery to overcrowded displacement camps,
"We have access to some camps and we don't have access to others," Kellenberger said. He declined to give further details when speaking to journalists on Wednesday at the launch of the 2008 ICRC annual report..
ICRC aid workers have access to some parts of Manik Farm, ICRC spokesman Marcal Izard told the Canadian Press.
Kellenberger said some of the people in the camps are being "interned" for security reasons. He declined to elaborate.
“There is important protection work to be done (in the camps). We want to visit those who are in clear detention,” he said.