Dr. Josef Mengele, the most notorious Nazi war criminal still at large, was seen in Paraguay as recently as 1982 working as a beekeeper, according to officials of a leading center for the study of the Holocaust.

Rabbi Marvin Hier, dean of the Simon Wiesenthal Center here, will tell a U.S. Senate committee Tuesday of information recently acquired from German-Paraguayan drug dealers that represents the latest account of the whereabouts and activities of the fugitive death-camp doctor, a center spokesman said.

Hier is one of the leaders of an accelerating campaign to track down Mengele and investigate the possibility that he might have been aided by U.S. officials in his postwar escape from Germany. The center's probe has produced testimony from two former members of the U.S. Army suggesting that Americans held Mengele sometime between 1945 and 1947.

A center spokesman said Hier will give the Senate juvenile justice subcommittee imformation gathered through at least two sources from Ricardo von Riefenstahl, a German-born bee expert in his 70s who allegedly lived with Mengele in Paraguay. Hier has spoken to West German authorities about von Riefenstahl, who is in a Bonn jail for smuggling cocaine.

A California businessman who has spoken to one of von Riefenstahl's business associates said the elderly bee expert, who taught at Asuncion University, reportedly lived with Mengele two years until late 1982 in a community 40 miles from the Paraguayan capital. Von Riefenstahl and other elderly German-Paraguayans said Mengele lived "a life of obscurity" while the government of Paraguayan President Alfredo Stroessner obstructed international efforts to find and return him to West Germany to answer murder charges.

The spokesman said the new information is important in locating Mengele and helping investigators who mistakenly thought that he might still be practicing medicine.

Mengele allegedly helped direct the gas-chamber murders of thousands of prisoners at the Auschwitz concentration camp and performed painful medical experiments on prisoner children, which are the subject of Tuesday's hearing.