NEW YORK (AP) _ Tellers are gathering, clerks are stocking deposit and withdrawal slips and security people are lengthening the line dividers as banks brace themselves for another ''Lost Friday.''

More than 80 million workers who are paid weekly, biweekly and bimonthly will get their checks on the same day - Sept. 28 - and most will make a stampede for the bank.

''It's a massive problem,'' Brace Pattou, a spokesman for Harris Bank in Chicago, said of the event, which will occur just four times this year.

To cope with the convergence of customers, Harris takes former tellers who do other jobs in the bank and puts them behind the counter. The bank also issues white carnations to lobby managers to make them ''visible and accessible when people have problems'' or, more likely, become impatient over the long lines, Pattou said.

Other banks forbid tellers from taking lunch breaks during peak noontime hours as transactions at the windows and automatic teller machines jump as much as 50 percent.

One way to avoid the mahem is for employees to have their companies deposit their paychecks directly into their bank accounts.

The practice is embraced by nearly all Japanese businesses and most Europeans. But in the United States only 17 million checks are deposited directly, according to figures from the National Automated Clearing House Association, a Herndon, Va.-based trade group.

Direct deposit is safe and efficient and relieves busy workers of a trip to the bank simply to dump money into an account. ''Why take the risk or lose time dealing with a paycheck,'' said Elliott McEntee, clearing house association president and chief executive.

But corporations and banks stand to reap big benefits themselves. The clearing house association estimates employers could save anywhere from 10 cents to 23 cents on every paycheck that is deposited directly.

Furthermore, the association estimates that conservatively, companies would increase productivity by up to $5 billion a year because employees would no longer need to take time out to visit their financial institutions. A recent study by the automated clearing house trade group found the average employee spends eight to 24 hours each year going to the bank during working hours.

For banks, which have long been criticized for trying to keep average customers at arms length, direct deposit would mean fewer in-person visits to the teller window - or 60 cents saved per deposit transaction. That could translate to tens of millions of dollars in weekly savings for the financial institutions, according to the association.

Then there is the issue of float, the time between the deposit of a check in the bank and payment. Businesses, which earn interest until checks are cashed, will lose some of their float advantage with direct deposit. But McEntee stresses that advantage will be more than made up in productivity savings.

The association has spent over $2 million in the past two years on a marketing campaign designed to encourage direct deposit among bank customers. McEntee plans to make a personal pitch to American Airlines' executives this week.

So far, the campaign has been met with reasonable success. McEntee figures that 100,000 companies are offering direct deposit to some or all employees, double the number three years ago.

Still, many people are reluctant to rely on an all-electronic pay system. ''It is clear from market research that some consumers want a paper check,'' McEntee said.

It provides ''a sensation of security - people think the paper check is good, but electronic payment is more secure,'' he said.

End Advance Thursday PMs, Sept. 27