Ronald Reagan has decided on his choices for several positions in his Cabinet, Edwin Meese III, the president-elect's top aide, said today.

"He has made definite decisions and he's in the process of implementing them now," Meese said on ABC's "Issues and Answers." Meese said the first Cabinet selections will be made public either at the end of this week or during the following week, when Reagan is scheduled to be in Washington.

He added that he expects the full Cabinet to be named before Christmas, and he reiterated that neither William Simon nor George P. Shultz had been offered a Cabinet post before the two took themselves out of the running last week. Their actions have not affected Reagan's timing or decisions in choosing his Cabinet, Meese said. Former ambassador Anne Armstrong, a campaign and transition adviser to Reagan, also has said she does not want to be considered for an administration job.

Meese, who will hold Cabinet rank in Reagan's administration will also coordinate foreign and domestic policy within the White House as Reagan's White House counsel, took exception to the way West German Chancellor Helmut Schmidt described the brief meeting Schmidt had with Reagan in Washington 10 days ago.

The German leader told the West German Bundestag last week that the two men were in full agreement on questions of East-West relations and arms control.

Meese said, however, that Schmidt did the talking during their meeting while "the president-elect primarily listened." Meese declined to characterize Reagan's views except to say he hoped that Schmidt and Reagan would see eye to eye.

Reagan had agreed to the meeting with Schmidt after declining to meet with Israeli Prime Minister Menachem Begin, and Reagan aides have expressed private annoyance at what they see as the West German chancellor taking political advantage of the session -- first extending it beyond a brief courtesy call to a 50-minute meeting, then referring to it extensively in the Bundestag speech.

On relations with the Soviet Union, Meese said he finds it interesting that Moscow has indicated it is looking forward to early talks about arms control with the Reagan administration.

He also said that the president-elect and his advisers are considering a number of options for dealing with the hostage crisis if the 52 Americans are still held captive by Iran when Reagan takes office Jan. 20.

"The president-elect doesn't have some secret cure-all" for the hostage problem, Meese added.

Meese said that the Reagan team still is working on plans to restructure the relationship between the White House staff and the Cabinet. Plans are being studied to use the Cabinet in new ways, he said.

A part of his role, Meese said, will be to bridge the gap between the Cabinet and the White House staff. Cabinet officers also will have direct access to the president, he added.

Reagan, who left Palm Springs today to return to Los Angeles after attending a benefit dinner Saturday night, said he would resume the task of selecting the Cabinet Monday.

He also said he would spend the first few months of his presidency concentrating on the economy. "I think for the first few months, anyone in our position ought to concentrate on the economic problems and getting started on that," he told a reporter who wanted to know if he would hold a summit with Soviet President Leonid I. Brezhnev.

Asked if he believed he could improve the economy soon, Reagan replied, "I don't know how soon. It took a long time to get in this mess but we are going to start."

On his arrival in Los Angeles, Reagan was asked if there would be a woman in the Cabinet. Reagan paused and said, "Uh [another pause], let me say there is quite a broad range of names that are being discussed."