The administration of Gov. Harry Hughes, battling accusations that it lied this year about the severity of problems in Maryland savings and loan associations, cleared a key legal hurdle today when a Circuit Court judge approved the sale of three thrifts to Chase Manhattan Corp.

With the stroke of a pen, Baltimore Circuit Court Judge Joseph H.H. Kaplan put the 70,000 depositors of Merritt Commercial, Friendship and Chesapeake savings and loans closer to gaining full access to their funds, some of which have been frozen since June.

Chase Manhattan, which narrowly won the General Assembly's approval of the savings and loan acquisitions last week, is expected to conclude the deal formally on Thursday, and it may free deposits as early as Friday, according to a lawyer for the New York banking giant.

Kaplan's action was good news for the Hughes administration, which spent last weekend attempting to deflect a barrage of criticism for not acting more aggressively on an Oct. 5, 1984, memorandum that outlined questionable business practices among some state thrifts.

The Maryland Savings and Loan Depositors Committee, representing 5,000 persons whose money is frozen at three large savings associations, has scheduled a rally for Wednesday night in Randallstown and another in Gaithersburg for next week. Last Saturday, the committee called for a federal investigation into the administration's handling of the thrift industry crisis and accused Hughes of lying about the severity of problems in the industry this year.

The 1984 memo first became public in Saturday's Washington Post. In that report, Hughes said he referred the memo to the appropriate government regulators, who the governor said replied by playing down the importance of the concerns it raised.

Criticism of Hughes' handling of the memo has reached key members of the General Assembly.

"Until that memo came out, people thought the governor was on top of the S&L issue," said House of Delegates Speaker Benjamin L. Cardin (D-Baltimore), who has generally supported Hughes in the state's five-month-old thrift crisis. "Now, they're starting to wonder."

Although Kaplan expressed displeasure with key elements of the Chase deal, he signed the brief order, making it possible for the Maryland Deposit Insurance Fund (MDIF), a state government agency, to live up to its part of the transaction by contributing $25 million to Chase.

"I am not thrilled with MDIF paying Chase $25 million, but I understand the necessity of it," Kaplan said minutes before signing the order. "I am not thrilled with the state of Maryland paying $25 million and the principal stockholder -- at the same time -- getting anything."

Under the terms of separate private agreements with Chase, Merritt Commercial owner Gerald S. Klein -- who is under criminal investigation for possible mismanagement of the thrift -- will retain some potentially profitable real estate ventures and be forgiven a $7.5 million debt to Merritt if he assists Chase for the next five years.

Opposition to those agreements nearly killed the Chase transaction when the legislature scrutinized the deal last week, and Kaplan said today he was sympathetic to those concerns.

"The legislature did not just rubber-stamp what the governor wanted," the judge said from the bench. "It acted perfectly properly in questioning the transaction."