Taking a step into the electronic age, the Treasury Department's Bureau of Alcohol, Tobacco and Firearms has begun requiring its largest taxpayers to transfer their payments to the government electronically, putting an end to the age-old excuse that "the check is in the mail."

As part of its new cash management reforms -- and to help head off criticism that the government doesn't pay its own bills on time -- the Treasury Department also has begun making its payments of $25,000 or more the same way.

In electronic fund transfers, banks simply move cash from the account of one party to another, with no exchange of invoices and checks.

As of Oct. 1, the BATF has required the approximately 500 liquor and tobacco companies that have annual excise tax payments of more than $5 million to pay the taxes electronically through a federal reserve bank or a bank that holds federal reserve accounts. The bureau now collects about $10 billion in excise taxes each year.

The change is expected to save the government $8 million a year, by allowing it to earn interest on the money immediately instead of letting the funds remain in taxpayers' accounts while checks work their way through the mail and the bureaucracy, according to Dot Koester, an agency spokesman.

"The industries have had all that float," Koester said. "This time the government will have it."

The government, of course, has always had the benefit of that same "float" when it mails checks to vendors or taxpayers who are entitled to a refund. So the government is making its largest payments through the same computerized account-to-account transfers that may make the checkbook obsolete.

"A corporate treasurer may look at me and ask, 'Why are you doing that?' " said Carole J. Dineen, who oversees Treasury's Bureau of Government Financial Operations. "I'm into saving money too, but in an even-handed way so we do not take advantage of others."

Electronic fund transfers have become increasingly common in the business world. Many insurance companies, for instance, have made arrangements to deduct their premiums directly from customers' accounts.

"It's revolutionized the way business does business," said Steve Tupper, a spokesman for the Office of Management and Budget. "What we're trying to do is revolutionize the way government does business."