In the fraudulent category, a longtime employee of the U.S. Forest Service in Oregon, Debra K. Durfey, wrote convenience checks worth more than $640,000 from 2000 to 2006 to a live-in boyfriend, who used the money for gambling, car expenses and mortgage payments

In a case the GAO deemed "abusive," the Postal Service spent $13,500 in 2006 on a dinner at a Ruth's Chris Steak House in Orlando, including "over 200 appetizers and over $3,000 of alcohol, including more than 40 bottles of wine costing more than $50 each and brand-name liquor such as Courvoisier, Belvedere and Johnny Walker Gold." The tab came to more than $160 a head for the 81 guests, the report said.

The GAO found that 41 percent of the transactions it examined did not follow government purchasing rules. The problem was worse with larger purchases: Forty-eight percent of transactions over $2,500 were in violation of federal rules, the report said.