On the eve of this year's legislative session, Maryland General Assembly leaders criticized Gov. Harry Hughes for failing to provide a detailed plan releasing $1.2 billion in deposits now frozen at four state savings and loan associations.

Senate President Melvin A. Steinberg and House Speaker Benjamin L. Cardin emerged from a 2 1/2-hour meeting with the governor this afternoon still in the dark about the plan that Hughes has promised to deliver for several weeks.

"He doesn't have a depositors plan yet," said Steinberg, who described himself as "frustrated and a little disappointed" by Hughes' failure to explain precisely how he intends to pay off more than 100,000 depositors at the four institutions that have been under state control since a crisis hit the state's thrift industry last May.

State officials have been exploring a range of options for paying off depositors from several sources and over periods of one to five years.

Money for depositors can be raised "in only a couple of acceptable ways, either through short-term bonds . . . or in the general budget or a combination of the two," said one government source.

Steinberg said he was expecting a decision on depositors at today's meeting with the governor, which was scheduled to resume this evening. Cardin was, too.

"It's difficult for me to start a session of the legislature and give direction to my membership without a plan," Cardin said. "If [Hughes] eventually comes in with a plan that's satisfactory to the members the frustration will ease quickly and the hard feelings won't last long. But if the plan is not acceptable . . . there could be lasting repercussions in the session because of the delay in getting this to us."

The remarks by Cardin and Steinberg signal a divisive beginning for the 1986 legislative session that convenes at noon Wednesday, at the same time that hundreds of angry savings and loan depositors are expected to demonstrate outside the State House.

The rally by depositors, who will be addressed by consumer advocate Ralph Nader and two leaders of a depositors' association in Ohio, will begin two days in which the news from Annapolis will be dominated by reminders of the thrift crisis that has dogged the Hughes administration for eight months.

On Thursday, the General Assembly will receive a long-awaited report on the causes and origins of the savings and loan debacle by the state's special counsel, Wilbur D. Preston Jr. A key element of Preston's 500-page report will be an assessment of the Hughes administration's responsibility for the financial crisis.

Hughes may recapture the spotlight Friday, when he is expected to address the General Assembly and present his proposal for depositors.

Hughes administration officials said today the final shape of the depositors plan could change dramatically if, in the next few days, the state completes arrangements for the sale of one or both of the Montgomery County thrifts under conservatorship.

The administration has been expecting federal approval of the takeover of First Maryland Savings and Loan Association by a federally chartered thrift in Pikesville, and has solicited bids for an acquisition of Community Savings and Loan Association.

"Everything is so fluid that anything he announces on Friday will depend on what happens" between now and then, said Melville S. Brown, director of the Maryland Deposit Insurance Fund.

The state is also looking for a buyer for Ridgeway Savings and Loan Association, a small Baltimore County thrift. Assuming the state arranges takeovers of First Maryland, Community, and Ridgeway, it will be left with the task of liquidating the assets of Old Court Savings and Loan, which is under state receivership. Depositors, whose claims exceed the thrift's assets by about $200 million, would be paid off by the cash generated from selling those assets and whatever additional state funds are necessary.

Hughes' failure to make public his plan for paying depositors drew an angry response today from one of the leaders of the Maryland Savings and Loan Depositors Committee.

Committee cochairman John McHale said, "We were promised something back before Christmas . . . and we still don't have our hands on a plan . . . . The current situation makes [Hughes] look like he doesn't have the leadership."