Nearly 20,000 people still live in transitional shelters, of which around 40 percent are in need of upgrades, the U.S. said in a statement.
America had earlier paid to build nearly 10,000 transitional camps, mostly in the Matara and Amapara Districts, through the U.S. Agency for International Development (USAID).
"We cannot forget the people who are still living with effects of the tsunami," said USAID Mission Director Carol Becker.
"Unless we follow up on our initial work of getting the tsunami-displaced into decent shelters, the communities run the risk of deteriorating into unsafe and unhealthy places."
Maintenance of infrastructure in the shelter communities will include repairing leaky roofs, constructing kitchen extensions, waterproofing wood structures, and improving access roads.
Power supply systems will be maintained and improved, and the inhabitants will be trained in the upkeep of their own communities.
The grant will also provide fire extinguishing equi