The partial shutdown of the U.S. Federal Aviation Administration (FAA) is expected to cost the federal government at least US$1.2 billion in tax revenue, as the impasse is likely to last until early September when Congress returns from summer recess, CNN reported Tuesday.

The FAA partially shut down on July 23, furloughing without pay nearly 4,000 workers as Congress failed to reauthorize the agency' s funding.

Due to the stalemate, the airlines stopped collecting certain passenger taxes at a cost of about US$25 million a day, the report quoted officials as saying. At that rate, the federal government will lose at least US$1.2 billion before Congress returns in September.

The funding bill, which includes a controversial extension of taxes that help fund the FAA, cleared the House of Representatives but failed in the Senate amid partisan disputes over labor rights and other issues.

The only possible resolution, the report said, is if the Senate approves the House bill. But that was deemed highly unlikely. The House adjourned for summer recess Monday night, and the Senate is to follow soon.

Despite the impasse, Transportation Secretary Ray LaHood stressed that essential personnel related to airport and air safety was not cut, saying "safety will not be compromised."