Top Republican political strategists, including veterans of President Reagan's campaigns, said yesterday that there is strong consensus among them that Reagan should abandon plans to lay a wreath next month at a German military cemetery.

Despite widespread agreement that the visit May 5 to Bitburg cemetery will be a "disaster," as several of them put it, the strategists said they had not thought of a way for Reagan to change his plans. Several said they hoped to come up with an alternative plan in the next week.

The strategists, who spoke on condition that they not be identified, also said Nancy Reagan had privately expressed concern about the cemetery visit and indicated that she would like to stem the controversy. Asked about the issue yesterday, she declined comment.

The concern among Reagan loyalists came as a nationwide Washington Post-ABC News poll shows that a slim majority of Americans disapproves of Reagan's scheduled visit to the German cemetery and wants him to cancel it. The poll also shows a drop in Reagan's "approval rating," the public's evaluation of how he is handling the presidency, to 54 percent, his lowest rating since October 1983.

The political strategists, most of whom worked on Reagan's two successful presidential campaigns, said they had discussed the cemetery visit among themselves but had not yet voiced their concerns to White House chief of staff Donald T. Regan or the president.

Reagan's plans to visit the cemetery have touched off strong protests from Jewish organizations and American veterans, but the president said last week that he would not change his plans because "all it would do is leave me looking as if I caved in in the face of some unfavorable attention."

Spokesman Larry Speakes reiterated yesterday that Reagan had no plans to change his itinerary. West German Chancellor Helmut Kohl has termed Reagan's decision to visit Bitburg, where some Nazi SS troops are buried, "final." Earlier, according to an administration official, Reagan himself had asked Kohl if the Bitburg stop could be skipped, but Kohl declined to change the president's itinerary.

In the past, some of the same individuals have been instrumental in convincing the White House that public opinion was shifting against Reagan or his policies.

For example, when Reagan made a critical remark about civil rights leader Martin Luther King Jr. in 1983, several of these strategists warned the White House about a damaging backlash among voters. As a result, Reagan apologized to King's widow, Coretta Scott King, and later sponsored a Rose Garden ceremony to sign a bill setting King's birthday as a federal holiday.

Late in 1983, these strategists privately urged the withdrawal of U.S. Marines from Lebanon, saying that support in Congress and the country was eroding. Reagan, who often insisted forcefully that he would not withdraw, later moved the Marines out.

Speaking of the Bitburg visit, one official, a veteran of Reagan's 1980 and 1984 campaigns, said: "The people who are political know what a disaster it's been. It's too late to undo the damage. The only way to get out of it is not to do it. There is no high side. Any good to come of it is moot -- it's whether Regan and his boys are willing to say they made a mistake."

A second official, instrumental in Reagan's first-term political successes, said, "There is a consensus that Reagan needs to find a graceful way out of Bitburg."

A third official, also a campaign veteran, said, "Everybody thinks this is a disaster -- we've got to find a way out. There are a lot of ideas, but none with enough support" to pass them on to the White House.

Other sources said the White House intends to remain silent on the issue.

The Bitburg controversy also came up yesterday at a White House meeting to discuss Republican fund-raising and the May 16 "President's Dinner," a fund-raising effort of House and Senate GOP campaign committees.

Wyatt A. Stewart III of the National Republican Congressional Committee said that "at this point it [Bitburg] has not had a critical effect," with $3.5 million already raised; $4.7 million was raised last year. Stewart said the "pressure point" on fund-raising would come before Reagan visits the cemetery.