Major corporations have begun to reassess their willingness to pay the health-care costs of retirees in the face of tough new accounting standards that will trim millions of dollars off their profit statements, leading benefit experts said yesterday.

Under new rules to be published later this year by the Financial Accounting Standards Board (FASB), the average corporation will be forced to show on their books the potential costs of health care for retirees six to 10 times greater than they currently do. Newer companies with younger workers may be forced to show an increase on their books of 20 to 25 times what they do now.

The accounting change will not affect how much a company has to pay each year for the costs of medical treatment. Rather, it will force companies for the first time to count their long-range health care costs as liabilities on their books each year, even though they haven't spent the money, and that in turn will lower the profits they show to Wall Street.

The FASB rule simply states that beginning in 1993, a company must either set aside money to pay for retiree benefit promises it makes to employees or show the cost of those promises as a liability on its balance sheet. Most corporations currently pay retiree health benefits as they occur and do not set aside any money in advance.

Diana Scott, project manager for the FASB health rule, said that almost all the companies used by the board to field test the new rules are now reassessing their retiree health-care plans. "One of the things that is happening is that it got people to focus on what they promised," Scott said. "The general reaction is that 'We never intended to promise that much.' "

Scott said the auto and steel industries would be hardest hit by the rule change because they have a much older work force and many retirees than most other industries.

A number of companies contacted yesterday said they were unable to immediately assess the impact of the new accounting rules on their balance sheets. But several benefits experts said most of their clients are looking to reduce the amount of money they spend on retiree health care, either by sharing costs with employees or tying the level of health benefits to the levels of service by an employee.

"Just about every major client we have is looking at it," said Joel Rich, a principal with William M. Mercer Inc., a benefits consulting firm in New York. "I think that by and large most employers who have retiree health plans are going to be forced to rethink what their goals and objectives are."

Mike Johnston, a principal with Hewitt Associates consulting firm in Cleveland, said companies are beginning to realize "they cannot afford to make the open ended, unlimited promises they have in the past. They're going to have to put some caps on it."

Johnston said that as a general rule of thumb his group predicts a six- to 10-fold increase in expenses on company books. "The number on the balance sheet will get very large very quickly," Johnston said. "We call it the gee-whiz effect. A company looks at the numbers, and they're so huge that all they can do is say 'Gee whiz.' "

Patricia Wilson, a principal with A. Foster Higgins & Co., a Princeton, N.J., consulting firm, basically agreed with Johnston's expense-increase estimates. "It's in the ball park," she said.

There was agreement among the consultants that most companies, unless they found themselves in dire economic straits, would not tamper with the health care of existing retirees, and would only nibble around the edges for older current employees. The biggest group targeted for change would be prospective employees.