A Congressional report released late Monday hedged in its support of automatic individual retirement accounts.

Automatic IRAs would be a significant step in inducing savings among the more than 50 percent of American households without employer-sponsored retirement plans, they would only bring “at best” moderate increases in retirement incomes, said The General Accountability Office, the investigative arm of Congress. Workers could waive their participation in automatic IRAs.

The median annual increase in retirement income was projected at between $479 and $1,043, depending on pre-retirement pay.

The report also warned automatic tax-deferred IRAs would sap a funding-strapped federal government of revenue of roughly $1 billion per year in the near term.

In 2011, according to the study, 45 percent of wage earners between 21 and 64 participated employer-sponsored pension plans while 54 percent had them available.

The median adjusted gross income for households without defined contribution plans or IRAs was $32,000, compared with $75,000 for those that did have them.

About 7 percent of households with no employer-sponsored pension plans would receive retirement income from automatic IRAs, the report said.

The study noted under current proposals investment options for automatic IRAs would be limited, with target-date funds being the default.