The chief judge of the U.S. District Court, responding to prosecutors' complaints of a "concerted effort to frustrate and delay" their investigation, yesterday ordered Mary Treadwell, executive director of Youth Pride Inc., to appear before a federal grand jury at 10 a.m. Tuesday.

In a rare personal plea to the judge, delivered to the courthouse Wednesday, Treadwell denied the prosecutors' accusations. Nevertheless, Bryant yesterday ordered her to appear at the grand jury's next meeting or face a contempt of court citation.

Since October 1979, federal investigators have been seeking a grand jury appearance by Treadwell to certify that she is the official custodian of the records of several Pride-related businesses under investigation and to provide a sample of her handwriting. All of the records requested have been submitted, but Treadwell has not appeared, despite four subpoenas.

Two weeks ago, the prosecutors asked Chief Judge William B. Bryant to declare Treadwell in contempt of court if she did not cooperate immediately. Earlier this week, Treadwell submitted a response, which Bryant would not allow to be made public.

Yesterday, in a one-page order directing Treadwell to appear, Bryant made only a passing reference to the response as "an apparent effort to explain the reasons for noncompliance."

Treadwell could not be reached for comment late yesterday. One source familiar with the response said it argued that her failure to appear was not a deliberate or willful attempt to avoid the grand jury, but rather the result of her financial difficulties in hiring and retaining a lawyer throughout the complex and voluminous investigation.

The source said Treadwell told Bryant she felt it was impossible for her to appear before the grand jury until she had a lawyer. Prosecutors have contended that they have consulted with four different lawyers in regard to the four subpoenas issued, and that the uncertainty about Treadwell's legal representation has slowed progress in the case.

Specifically, Bryant ordered Treadwell to appear before the grand jury at its next meeting, scheduled for Tuesday, and "to answer such question that pertain solely" to the authenticity of corporate records which have previously been turned over to the grand jury. Those records were in Treadwell's custody.

She will not have to answer general questions because she is one of the targets of the probe into allegations that she and two other officials of P.I. Properites, a real estate spinoff of Youth Pride, stole, misappropriated and diverted $600,000 from the federal government and low-income tenants of the Clifton Terrance Apartments in Northwest Washington. Treadwell has denied any wrongdoing.

Such an appearance before the grand jury by a custodian of records is usually a routine matter. The witness, in this case Treadwell, would be asked under oath if the documents are authentic and if all the records subpoenaed have been turned over to the grand jury.

The latter declaration is considered particularly important to prosecutors to assure that they are not unexpectedly confronted with previously undisclosed documents if the case goes to trial.

Bryant's order marked the second open dispute in the Pride investigation, which, after more than a year of quiet acivity, has become increasingly active in the past month.

Last week, in an rare open hearing in the case, assistant U.S. Attorney William D. Pease disclosed that Treadwell failed to file income tax returns for 1979 through 1979. The late returns were filed last June, months after Treadwell had become a target of the grand jury investigation.

In that hearing, Bryant said that prosecutors could question a New York accountant who helped prepare those returns, overruling strong objections from the accountant's lawyers.

The grand jury investigation began in the fall of 1979 following reports in The Washington Post that Treadwell, Robert E. Lee Jr. and Joan M. Booth stole and diverted the funds from Clifton Terrace. Lee, the firm's former general manager, has refused to discuss specifics. Booth, Treadwell's sister who acted as project manager at the apartment complex, has declined to be interviewed.

The Washington Post reported last month that the first 10 months of investigation, the U.S. Attorney's office was forced to switch the case from one grand jury to another and then to a third, when it was learned that a member of the first grand jury was leaking information about that panel's secret proceedings.