The hasty appointment of a new White House communications director has stirred fresh controversy within the strife-ridden Reagan administration and widened the rift between First Lady Nancy Reagan and White House chief of staff Donald T. Regan, informed sources said yesterday.

The chief of staff yesterday told aides at a senior staff meeting that the "East Wing" was to blame for an apparent oversight in checking the background of the new appointee, John O. Koehler, who belonged to a Nazi youth group in his native Germany as a 10-year-old. Regan later explained he was referring to Nancy Reagan, whose staff is based in the East Wing of the White House.

Sources quoted Regan as acknowledging he had interviewed Koehler, but the chief of staff added that Koehler's experience in the youth group "was not on his resume."

White House spokesman Marlin Fitzwater said President Reagan stands behind the appointment of Koehler, a veteran Associated Press executive, who was named to succeed Patrick J. Buchanan. But Fitzwater added that the White House had not known that Koehler had been a member of a Nazi youth group.

The controversy within the White House was not over this aspect of Koehler's past but rather over what several sources described as the rushed manner in which the appointment was handled. They said that the appointment was pushed by Nancy Reagan and U.S. Information Agency Director Charles Z. Wick, whom Koehler had served as a consultant. The appointment was announced Thursday.

"It was done quickly and without running the usual traps," said a senior White House official. Other sources said Regan did not know Koehler was being hired, although Fitzwater said yesterday the chief of staff did interview him at the recommendation of White House personnel chief Robert H. Tuttle.

Fitzwater said Koehler volunteered yesterday to meet with Tuttle "to see that all parts of his record are clearly understood," and Koehler later flew home to Connecticut, where the Associated Press quoted him as saying, "I start to work March 2. It did not affect my appointment."

Informed sources said that Regan was unusually blunt yesterday in trying to shift the blame to the First Lady for any questions about the Koehler appointment. They said the incident aggravated tensions between Regan and Nancy Reagan that have been simmering over her efforts to oust Regan and over the pace at which Reagan resumes full activities after last month's prostate surgery.

Earlier this week, sources said the First Lady had not been talking to the chief of staff, and one official said Regan hung up the phone while talking with her in a dispute over scheduling. Regan has been the target of increasing criticism from Republicans expressing concern that the White House seems paralyzed by the Iran-contra scandal.

Following a report by NBC News Thursday night, Koehler, 56, said he had belonged as a youth to Jungvolk, which he described as "the boy scouts run by the Nazi party." He said it was irrelevant in judging his qualifications for the White House post.

Others agreed. Nathan Perlmutter, national director of the Antidefamation League of B'nai B'rith, said in a statement, "To judge a 56-year-old person by his association as a 10-year-old is ludicrous logic and mean politics."

Koehler, a native of Dresden, joined the U.S. Army in 1954 and stayed in the Reserve as a captain. He retired from the Associated Press in 1985 after 28 years of service. He became a consultant to Wick and was offered the White House job "based upon his record and his qualifications," Fitzwater said, citing his "distinguished record with the AP and the USIA. He comes highly recommended."