WASHINGTON - A 2005 voluntary federal ban on the use of credit cards to purchase cigarettes online, as well as a ban on commercial shipping of online cigarette purchases has sharply reduced the sale of online cigarettes, U.S. News & World Report reports.

Implemented to address to widespread flouting of cigarette taxes with online purchases, the ban was an agreement between major credit card companies and private shippers, including UPS and FedEx.

"Most Internet vendors offer tax-free cigarettes, making them cheaper than those sold at stores," said Kurt Ribisl, author of a study that traced the effectiveness of the ban. "This undermines the impact that higher prices have on reducing smoking."

Post-ban, Ribisl??s team found that many online vendors went out of business, while the 50 most popular websites experienced a 3.5-fold drop in sales.

Among active online cigarette vendors, the number that accept credit cards or PayPal has dropped from nearly 100 percent to just over 37 percent, with fewer than six percent offering commercial shipping, compared with about 32 percent pre-ban.

Since the ban, payments have been made primarily with personal checks and they shipped initially with the U.S. Postal Service, which was not part of the 2005 ban. However, a federal law passed last year defines tobacco as "non-mailable matter," sharply curtailing its part in online cigarette sale shipments.

Ribisl said the ban has implications for controlling the sale of other restricted goods.

"This promising approach to controlling the sale of restricted goods online has implications for regulating other products, such as alcohol, firearms, quack cures and medicines sold without a prescription," Ribisl said.