City officials have mailed notices to more than 3,500 Oahu residents who receive federal rent subsidies that some may lose their housing assistance if Congress reduces funding for the program.

“The worst-case scenario will be that we must terminate families off the program,” wrote Sam E.H. Moku, director of the city Department of Community Services.

“We do not mean to alarm you, but need to warn you in case the budget passed by Congress forces us to reduce the number of families on the program,” the letter said.

The city received $41.5 million in federal money in 2010 to help thousands of families pay a portion of their rent under the Section 8 assistance program.

City housing officials said if there are cuts, reducing the number of recipients would be the last option.

When Congress cut rent subsidies in 2008, city officials revised housing standards required by the program and subsidy levels rather than cut families from the program.

Moku said families who are terminated may reapply for assistance once the waiting list is reopened. But the program has not accepted new applicants since 2005.