BONN, JAN. 15 -- Police searched the offices of two West German nuclear companies today but found no conclusive evidence to support allegations that weapons-grade nuclear material may have been shipped illegally to Libya and Pakistan, the government said.

The West German nuclear fuel manufacturing company Nukem and its shipping subsidiary, Transnuklear, both of whose premises were searched, denied that they ever sent abroad any radioactive material suitable for making nuclear arms.

The International Atomic Energy Agency and the European Atomic Energy Community expressed doubt that weapons-grade nuclear material could have been exported, but they did not rule out the possibility.

Nukem and Transnuklear, based at Hanau in the central German state of Hesse, have been under investigation for nine months in a West German-Belgian nuclear waste shipment scandal.

The inquiry took a dramatic turn yesterday when the federal government in Bonn said that prosecutors were studying information suggesting that Libya and Pakistan may have received nuclear material for making bombs.

The Swedish government said that it has been investigating reports of such shipments since the beginning of the week. One or more representatives of a Swedish nuclear processing firm allegedly received part of a total of $12 million in bribes that are said by investigators to have been paid in the nuclear waste shipment affair.

A woman informant, the source of the allegations in West Germany about shipments to Libya and Pakistan, was questioned by investigators today. The government declined to identify her, but the Reuter news agency quoted unidentifed Hesse state government sources as suggesting that she was a reporter for the West German magazine Stern.

West German Environment Minister Klaus Toepfer told Parliament that no evidence has been found that would support criminal charges of foreign shipments of weapons-grade material.

Nukem said that two drums of radioactive material, thought to be missing, were only partially full and that their contents had been repacked in other drums.

Paul De Jonghe, acting director general of the Nuclear Energy Research Center at Mol, Belgium, which has been implicated in the scandal, said there was "no trace" there of shipments of weapons-grade nuclear material to or from Libya or Pakistan.