The independent counsel investigating former Justice Department official Theodore B. Olson asked the Supreme Court yesterday to allow her to pursue the case -- including possibly seeking Olson's indictment -- while the constitutionality of the independent counsel law is on appeal.

Independent Counsel Alexia Morrison asked Chief Justice William H. Rehnquist to stay entirely the effect of a federal appeals court decision last month striking down the independent counsel law as an unconstitutional encroachment on the separation of powers.

The appeals court last week agreed to let Morrison appeal the decision to the Supreme Court but expressly forbade her from taking any other action in her investigation of Olson for possible perjury before a House subcommittee investigating the Environmental Protection Agency Superfund scandal.

In the papers filed yesterday, Morrison said that restriction threatened to irreparably harm her case against Olson because the five-year statute of limitations on perjury is about to expire March 10.

The limited stay granted by the appeals court, she said, puts Olson "in the unprecedented position of being beyond the reach of federal law enforcement for some indeterminate period."

Morrison noted in a footnote, however, that her case would not become entirely moot after March 10 because there are other "theories of potential prosecution," which she did not specify.

She asked Rehnquist to restore her option to return "a sealed, protective indictment" or to reach an agreement with Olson extending the statute of limitations.