The Senate committee charged with drawing new congressional districts for Maryland voted unanimously today to begin the job this session, surprising Gov. Harry Hughes and House legislative leaders who had planned to put off the task.

The proposal by the Senate Constituional and Public Law Committee that the General Assembly complete a congressional redistricting plan by mid-April was quickly discounted as unrealistic by House leaders. But Sen. Edward T. Conroy (D-Prince George's), the committee chairman, said that he will hold hearings and begin work on a plan even if Hughes and the House leaders do not go along.

"I'm not saying we're going to come up with a plan in 1981, but we're going to try," Conroy said. "Reapportionment [for state legislative districts] and redistricting is one of the most difficult jobs the legislature has. It just makes sense to try and do some of it this year."

Under state law, the General Assembly cannot draw new state election districts until its 1982 session. However, the law does not specify when congressional districts must be completed.

Conroy's committee sent a letter today to Hughes, House leaders and members of the congressional delegation requesting that the congressional lines be redrawn now. "Even if we don 't finish, we will make a good start and might avoid having a special session or having to do it all next year," Conroy said.

Conroy said he had met with Senate President James Clark, and that Clark had "readily supported" his plan. I'm sure we will have hearings and get started," he said. "We have our prerogatives, and it makes sense that somebody starts it off."

Hughes' legislative aide, John O'Brien, said that while "We don't have any objection" to legislative committees working on redistricting this year, "Our plan is to submit a redistricting plan for both legislative and congressional districts next year." And House leaders, who were taken by surprise by the Senate committee vote, said bluntly that a plan could not be done this session.

We can't do it," said House Speaker Benjamin L. Cardin.

Cardin and other House leaders said that they did not think the legislature could possibly finish a redistricting plan this session because the final figures from the 1980 census will not be available until April 1, even if they are not delayed by court challenges.

Conroy responded that he believed his committee could work with the now avialable preliminary census data "and save the final decisions until we have the hard data."

Cardin said he would have no objection to the Senate committee beginning work on a redistricting plan "as long as it doesn't detract from the cooperative redistricting effort between the House, the Senate and the governor."