BONN, JAN. 14 -- Prosecutors are investigating whether radioactive material suitable for making nuclear weapons may have been delivered to Libya and Pakistan in recent years by persons implicated in a Belgian-West German nuclear waste shipment scandal, Environment Minister Klaus Toepfer said tonight.

The West German nuclear shipment company Transnuklear, which is at the center of the nine-month-old scandal, may have transported weapons-grade nuclear material to the northern port of Luebeck for later shipment to Libya and Pakistan, Toepfer told journalists after an emergency meeting of a parliamentary environment committee.

Indications are that the nuclear material may have come from a Belgian processing plant at Mol, near Antwerp, he said.

"Information to this effect is being investigated," Toepfer said.

The investigation was made public as the federal government ordered the immediate shutdown of the Nukem nuclear fuel manufacturing company, which owns a controlling interest in Transnuklear.

No one was available at either Transnuklear or Nukem to comment on the allegations.

The Nukem company, based at Hanau near Frankfurt in the central state of Hesse, was closed because it failed to inform authorities of irregularities in Transnuklear's transportation and processing of nuclear waste, Toepfer said.

Earlier investigations into the scandal have focused on allegations that $12 million in bribes were paid to facilitate shipments of illegally labeled nuclear waste between the Nukem complex and the Belgian plant. Two suspects have committed suicide since the original investigation began.

It is unclear why the shipments might have been mislabeled and why such large bribes supposedly were paid. Until now, media reports have speculated that the law allegedly was broken as part of a murky attempt by Transnuklear to preserve its dominant role in the West German nuclear waste shipping industry.

This evening, however, television news commentators suggested that the irregularities may have been designed to conceal illegal exports of nuclear material.

Transnuklear, which was responsible for shipping the nuclear waste materials between West Germany and Belgium, lost its license last month after it was disclosed that more than 2,000 drums had come back from Belgium to West Germany with radioactive substances that were not declared on their labels.

Some of the drums allegedly contained material that was significantly more radioactive than it was supposed to be, and some of these drums may have been meant to be sent overseas to make weapons, West German television reported.

The investigation into possible shipments to Libya and Pakistan was opened yesterday in Hesse after authorities there received information indicating that such shipments had been made, Hesse state Environment Minister Karl Weimar said. He did not identify the source of the information, although West German media reports suggested that suspicions were aroused by a report earlier this week by the Belgian magazine Viv/L'Express.

The magazine said its information about alleged shipments to Pakistan was stronger than that pertaining to Libya.

Toepfer said that the investigation included an inquiry into possible violations of the Nuclear Non-Proliferation Treaty.

The 1968 treaty, which West Germany has signed, requires countries to ensure that their commercial nuclear activities do not make it possible for non-nuclear nations to obtain atomic weapons.

The government plans to inform the International Atomic Energy Agency in Vienna and the European Community of its investigation, Toepfer said. He briefed Chancellor Helmut Kohl by telephone this evening.

Toepfer said that the suspicions about possible shipments to Libya and Pakistan were based on only one source. But Volker Hauff, a spokesman for the opposition Social Democratic Party, said after hearing a briefing on the subject from Hesse minister Weimar that the allegations were based on several sources.

Hauff said that the nuclear material suspected of having been exported illegally came from members of the 12-nation European Community. It "probably" came from the Belgian plant, he said.

The latest allegations were certain to provoke intense controversy in West Germany and embarrass Kohl's government. His center-right coalition has strongly supported nuclear power, while the Social Democrats favor a gradual phase-out of nuclear plants.

The radioactive waste that allegedly was shipped illegally back to West Germany from Belgium included cobalt, cesium and plutonium, officials said.