The recent defection of a top-level Romanian intelligence official - which normally would be a quiet coup for the West - has touched off a serious political battle here and added another touch of uncertainty to U.S. West German relations.

Information supplied to the CIA by the defector, Lt. Gen. Ion Mihai Pacepa, has been used to alert other Western government, reportedly including France and Austria, about penetration by Romanian agents. Details have been kept under wraps and Pacepa reportedly is still being interrogated in the United States by the CIA.

In West Germany, however, leaks about the case to conservative, opposition-oriented newspapers have touched a nerve in a country where spy stories often are almost routine.

The differences this time is the alleged cast of characters, which includes a major figure on the left of Bonn's ruling Social Democratic party; the timing, just a few weeks before a crucial state election; and the political mood in both Bonn and Washington, where leaders of both countries would like to feel more confident about the other.

So far, West Germany is known to be investigating two officials as alleged communist agents. One is Joachim Broudre-Groeger, 34, an aide to Social Democratic Party manager, Egon Bahr, who was the strategist behind former chancellor Willy brandt's innovative policy toward Eastern Europe.

The other is Uwe Holtz, 34, a Social Democratic deputy whose parliamentary immunity was lifted by the legislature this week.

Both officials have denied any involvement in espionage.

Brandt, now the chairman of the Social Democrats, sees in the affair a smear campaign orchestrated by right-wing forces and "enemies of detente" in West Germany and other countries, possibly including some in the United States.

Conservative leaders see the revelations as another indication that the left wing of Chancellor Helmut Schmidt's ruling party is tampering with notions that could jeopardize Bonn's attachment to the Western alliance and lead it instead into accommodation with the Soviets.

Intelligence officials indicate they see no plot from the left or right, but a situation in which a well-placed defector came to the West with a lot of what is viewed as solid information, some of which was leaked here for political purposes.

The leaks, in fact, mey have come so soon that they will make it difficult for security forces here to collect evidence against those under suspicion.

Informants close to the situation say that Pecepa did not name individuals but rather provided several leads which West German security forces then followed up.

Officials from Bonn's Office for the Protection of the Constitution, similar to the U.S. FBI, were understood to be present at the CIA interrogation of Pacepa, who defected July 29 while on a trip Cologne in West Germany.

There is some suspicion that the leaks could have come either from intelligence or federal criminal or prosecution offices, each of which has a share of political conservatives in the upper ranks.

The key press report came in the daily Die Welt, the flagship of the conservative publishing empire run by Axel Springer. It said information supplied by Pacepa indicated that Bahr had drawn up a plan under which West Germany would withdraw from NATO in return for a Soviet pledge of nonaggression and reunification of the two Germanies. The paper said the Soviets had been informed about the plan by Broudre-Groeger.

That story sent the government through the roof, in the words of one official, and Bonn asked for a formal U.S. statement. The carefully worded State Department reply said the United States "has neither documentary nro any other evidentiary material" which says that Bahr had made such proposals.

The statement leaves open the question of whether the United States has other less formal indications, of Bahr's proposals, with fewer specific qualifiers.

Bahr, in a television interview last night, denied any thoughts of West Germany ever leaving the Western alliance. He said this was "an old story" of 1968 vintage, when, he said, "thinking papers or models" were developed and that it had now been dug up before the state elections.

"I'm sure our statement, nevertheless, draw Washington deeper into the controversy. The foreign policy spokesman of the opposition Christian Democrats, Werner Marx, suggested that the United States had delivered the requested "whitewash notice."

Bahr is a major target fo the conservative opposition here as a possible symbol, in their eyes, of naive flirtation with the Soviets.

Bahr is, in fact, something of a maverick even within his own party, an articulate and serious man and a nationalist who keeps the goal of German reunification in front of him. But he serves a West German government which today is much more conservative than the Brandt government he once served.

Bahr's links to the Soviets were also the subject of an article by columnists Evans and Novak last month which has contributed to the idea in some government circles of a coordinated campaign to get the Social Democrats, through Bahr, at a time when the country is becoming more conservative.

In May, White House national security advisor Zbigniew Brezinski was also widely reported to have told a West German visitor that Bonn "seemed to be engaged in a process of self-Finlandization," meaning an accommodation with the Soviets.

Chancellor Schmidt also raised soem eyebrows in his own Foreign Ministry this spring when he dispatched Bahr to Moscow to discuss the visit of soviet President Leonid Brezhnev to Bonn. Bahr had been the stronest critic of the U.S. neutron weapon proposal and so this choice, despite Bahr's good connections in Moscow, fed some ammunition to the critics.