A pension industry spokesman warned yesterday that an increasing number of employers will decide to abolish their plans altogether next year if they are forced to pick up the tab for benefits that declining industries cannot pay.

Robert A. Georgine, chairman of the National Coordinating Committee for Multiemployer Plans, urged the Senate Committee on Human Resources to enact emergency legislation to delay mandatory insurance coverge for up to two years. Under the law, the Pension Benefit Guaranty Corp. will be required to insure the pensions of beneficiaries in all multiemployer plans starting Jan. 1. The coverage is now optional.

PBGC is a government agency that support itself through premiums levied in insured plans. It released a study recently showing that 40 plans covering 385,000 workers in declining industries are in danger of collapsing within five years and leaving $350 million in unfunded liabilities. The industries include millinery, footwear, long-shoremen and milk deliverers.

Another 200 plans covering 1.2 million employees were found to be experiencing "significant hardship," which could result in termination, although not necessarily within five years. These plans have some $3.5 billion in unfunded liabilities.

The endangered plans cover 20 per cent of the 3 million persons in multiemployer plans.

Georgine proposed use of general government revenues, rather than pension premiums paid by healthy plans> to pay the beneficiaries of these declining industries pension plans.

"To fund such liabilities through premiums imposed on a per capita basis on the participants in other multiemployer plans would break the backs of those plans," he said. (Employers are not required to provide pension plans for workers, but if they do, the plans must conform to stringent rules.)

There would be little popular support for such a government bailout, according to PBCG's acting director, Matthew Lind. Subcommittee chairman Harrison A. Williams (D-N.J.) has asked PBGC to submit a proposed solution by nextsummer.

Yesterday was the first in a series of oversight hearings to make what Williams termed "a detailed analysisof ERISA (the Employees Retirement Income Security Act of 1974) and the problems appearing." Multiemployer plans were one of the weaker sections of ERISA.

Another unforseen problem was the consequences of the Daniel case, which held that an employee's pension plan is a security, subject to antifraud provisions of th Security and Exchange, Daniel alleged that he was not told an involuntary break in service would cost him his pension and therefore he was defrauded.

ERISA provided that no benefits would be granted retroactively, as in the Daniel case, but Georgine contended yesterday that a Supreme Court ruling upholding Daniel would have this effect.

If enough retired workers were granted once-denied benefits, it would undermine the solvency of current plans. For this reason, Karen Ferguson, director of the Pension Rights Center, urged that the Daniel decision be upheld.