The Treasury Department is expected to send to Congress this week a report that could determine whether private companies will be allowed to sell anonymous "bearer securities" backed by U.S. government bonds to foreign investors.

The Treasury was supposed to send the report on Sept. 1 in response to a Senate resolution last month condemning the issuance of such unregistered securities. The Senate was concerned that American citizens or residents could evade U.S. taxes by purchasing the bonds, which keep the name of the bondholder completely anonymous.

However, a Treasury spokesman said that both Treasury and congressional officials decided to delay the report until Congress returned from its Labor Day recess.

The nonbinding resolution was introduced by Sen. Howard M. Metzenbaum (D-Ohio) after several members of Congress became concerned about a plan by a group of securities firms and banks to purchase $1.7 billion of 30-year government bonds and repackage them for sale overseas as bearer securities. The Treasury Department also had been considering issuing its own bearer bonds directly, to raise capital in the lucrative foreign investment market.

Bearer bonds are popular abroad, where investors prefer to buy securities anonymously.

Metzenbaum had said that if Treasury Secretary Donald T. Regan didn't act to curtail such sales by private companies, "I definitely will introduce legislation" to stop it. "I will keep on this subject until I'm satisfied," Metzenbaum said.

The Treasury decided against issuing its own bearer bonds and announced that decision after the brouhaha over the plans by the private companies. However, Regan said he had made his decision before the Metzenbaum amendment condemning the private firms' plans was introduced.

Meanwhile, Treasury announced Friday that it will send two top officials to Japan, London, Zurich, Frankfurt and Amsterdam this week to reassure officers of major financial institutions there concerning the issuance of special registered securities to foreign investors later this month.

These special registered securities would allow bondholders and interest recipients to keep their identities hidden from the U.S. government -- as is the case with bearer bonds -- but would require banks and other institutions to certify that the bond owner is not an American citizen or resident.

The Treasury is eager to raise money overseas because it takes pressure off domestic capital markets and helps lower interest rates. The government's interest expenses and the federal budget deficit are thereby reduced.

However, some securities firms and institutional investors abroad were concerned that they would have to disclose the names of their clients to the U.S. government and provide other types of documents to certify that the bond purchaser was not an American taxpayer.

The Treasury is attempting to attract business back from the Eurobond market, which has mushroomed to $135 billion -- about $36 billion of which represents U.S. corporate bonds. Foreign investors own about $100 billion in Treasury securities.

Treasury officials had estimated that if European investors participated more fully in purchases of Treasury securities, the government could save about $1.5 billion annually in interest costs.