Metro officials moved yesterday to strengthen curbs on fraud and wrongdoing by appointing a high-ranking General Accounting Office administrator to head the agency's newly expanded auditing office.

John D. Heller, assistant comptroller general for policy at GAO, was named Metro's auditor-general, a position established in response to complaints by federal investigators. A report last year by the U.S. Transportation Department's inspector general warned that Metro was vulnerable to fraud and other abuses because of lax management controls.

"I'm concerned about the controls," Heller said yesterday. His new Metro office, he said, will investigate suspected wrongdoing, seek to ensure adequate safeguards over financial transactions by Metro employes and take steps to prevent abuses by private contractors hired to build the multibillion dollar rail system. Heller, 50, will assume the $67,765-a-year post April 4.

At the same time, Beverly R. Silverberg, a public information specialist for the U.S. Transportation Department, was appointed Metro's public affairs director. She will succeed Cody Pfanstiehl, who retired last September after 21 years as Metro's spokesman. Silverberg, 39, will start work at the $55,998-a-year job April 11.

The transit authority took another step to strengthen financial safeguards yesterday by asking private accounting firms to submit proposals for doing management audits. Metro's board of directors recently moved to ensure increased independence for these audits by placing the outside auditors under the board's control rather than under the Metro staff.

Heller's office is expected to be expanded next year to 26 full-time and five temporary employes, an increase of five staff members. Officials said Heller may request additional employes later. His appointment followed the resignation Oct. 31 of Russell R. Rushton as audit director. The higher ranking position of auditor-general was created to give the new administrator broader authority.