The Maryland General Assembly, with only two working days before adjournment, today moved closer to resolving differences over key legislation to restrain health care costs. But the legislature still faces potential last-minute snags on bills banning phosphate detergents and granting banking privileges to Citicorp.

The assembly set a pedestrian pace today after a frenetic night that saw passage in separate houses of measures banning phosphate detergent and allowing Citicorp to open operations in the state. Also Thursday night both houses passed legislation legalizing a limited return of slot machines to Maryland's Eastern Shore. The measure now goes to the governor, who has expressed reservations about signing it.

Although the legislature broke early for Good Friday and Passover observances, six members of a House-Senate conference committee reconciled most of their disagreements on Gov. Harry Hughes' package of health care legislation, with the House, and Hughes, forced to concede on a number of critical points.

The health care legislation, which was generally considered one of the centerpieces of Hughes' legislative program, is expected to be enacted on Monday. But most legislators say it will be considerably diluted from the governor's proposal, which included measures to set limits on hospital revenues, to regulate purchases of medical equipment and to establish at least a temporary moratorium on hospital construction.

In addition to tying up loose ends on dozens of minor bills, the legislature on Saturday may begin to resolve disagreements on the phosphate bill, which would ban the sale of detergents containing phosphates for three years.

Supporters of the ban are anticipating opponents to attempt a number of parliamentary maneuvers on Saturday to prevent final enactment of the ban, which has been approved in different versions by both the House and Senate.

Legislative leaders also are attempting to avoid any 11th-hour entanglements on the Citicorp legislation and a related regional banking measure, two companion bills over which the House and Senate are still at odds.

Late Thursday, the Senate gave overwhelming approval to a bill that would establish an indefinite period of banking between Maryland, the District of Columbia and 14 other states, including Pennsylvania. That regional banking bill, which moved to the House today, is sharply different from a House-approved bill that excludes Pennsylvania and calls for only four years of regional banking. Several delegates have vowed to contest the Senate bill.

The House reaction to the Senate banking bill is crucial to the survival of the so-called Citicorp bill, which would allow banks outside the region to establish branches in Maryland if they meet certain job and investment requirements. The Senate merged the two bills so that if the regional banking proposal dies, then so will the Citicorp bill.

Hughes summoned House Speaker Benjamin L. Cardin (D-Baltimore) and two key delegates to his office today to press for the speedy approval of the two banking bills, which he has pushed for more than a month as part of a deal under which Citicorp would establish a credit card center, and about 750 jobs, in Hagerstown.

Cardin said later that he protested to the governor about the Senate's inclusion of Pennsylvania in its regional banking bill. He argued that including Maryland's northern neighbor violates the recommendation of a task force that Hughes named last year to study interstate banking.

House and Senate leaders said today they expect few problems in the House accepting the Senate changes to the Citicorp bill.

Neither do they anticipate any significant roadblocks to enactment of Hughes' health care package, which a conference committee is expected to send back to the full House and Senate tomorrow. Final passage by both houses is expected on Monday, the last day of the session.

The conference panel recessed today without resolving a major disagreement on one bill in the package that originally sought to make physicians obtain certificates of need from state regulators for major medical equipment. They also have not resolved how many specific exemptions there will be to another measure that imposes an immediate moratorium on hospital building projects until October.

The committee did, however, reconcile the remainder of its differences on the seven bills sought by Hughes, and despite upbeat declarations by one of the governor's aides, the package has undergone far-reaching changes since it was introduced two months ago

Not only has the legislature rejected Hughes' proposed overall cap on hospital revenues, but the conference committee has refused to approve another provision that would have granted the governor the permanent authority to impose future hospital building moratoriums. Also, the panel has authorized more than a half dozen exemptions to the emergency moratorium.

However, the legislature is expected to enact other bills in the package, including a measure to force hospitals to implement "utilization review" programs as a means of weeding out unnecessary care and another that encourages hospital mergers and gives state regulators the power to close hospitals if they do not cut back voluntarily on unused beds.

"We got very significant provisions out of the legislature," said Hughes aide Andy Wigglesworth.