Former congressman Eugene Keogh, the author of the tax relief legislation on self-employed persons retirement plans, says the federal government hasn't quite finished its job in the pension area.

Keogh, now in a private law practice in New York, has called for legislation for the sector of the nation he describes as "underpensioned."

Under the current law, employees who are covered by their company's pension plan, no matter how weak it is, cannot open an Individual Retirement Account to add to tax deferred income to his retirement funds. Keogh thinks this has left many Americans without adequate old age coverage.

But, he said recently, "I don't think Congress would want the Keoghlimits (for broader legislation). I think it would be easier to argue for the IRA limits."

The Keogh provisions permit individuals to put aside up to 15 per cent of their annual income to a maximum of $7,500. The IRA legislation set limits of up to 15 per cent of annual earnings to a ceiling of $1,500.

"That way the pensionless and underpensioned would have the same benefits under IRA," he said.

The Treasury Department, however, has made know its opposition to further tx deferral plans because of their impact on the government's annual income. Not only would the kind of legislation favored by Keogh be expensive, the complexity of designing such a program to adequate compensate for the wide range of private company pension benefits may make it unworkable, Internal Revenue Service staff members said.

"The variety of plans in the private sector and their incredible contrasts among some of the provisions and amounts involved would require several years' of study just in identification," one IRS attorney said. "And then we'd have to develop proposals to fill in the gaps between the bad plans and the adequately funded plans. It would be a nightmare that I hope we are not forced to undertake."

Several bills to close the gap for the underpensioned currently are pending in both the House and the Senate, sources pointed out, but none have reached working committees' agendas yet.