West Germany, disputing allegations by the U.S. government, says it has no evidence that West German firms were helping construct a chemical weapons plant in Libya.

But Chancellor Helmut Kohl's administration said Monday it would continue to investigate U.S. accusations that Imhausen-Chemie Co. and two other firms played a key role in building the plant, which the Reagan administration has threatened to destroy if it is found to be manufacturing chemical arms."The inspectors are checking whether there are records of any exports of restricted chemical components - the type that could be used to manufacture toxic gas or other chemical weapons," a Finance Ministry spokesman said.

He said the examination began Friday and "no evidence has turned up so far."

Norbert Shaefer, spokesman for the Bonn government, said Monday that three companies - which he did not name - were being investigated in response to allegations of violations of foreign trade laws.

Schaefer said U.S. officials told Kohl during a Washington visit Nov. 15 that they suspected German companies were involved in the construction of a vast chemical weapons plant in Libya.

A spokesman for the state attorney's office said Monday there was "not enough evidence" to warrant legal action against Imhausen-Chemie, which is based in southwest Germany.

Speaking on West German Radio, the company's president, Juergen Hippenstiel-Imhausen, said Imausen-Chemie did not export chemical components to Libya and did not have the know-how to manufacture chemical weapons.

West Germany is expected to adopt legislation this month to tighten export controls. Washington earlier criticized loopholes in regulations concerning export of restricted West German military, chemical and nuclear technology to Third World and communist countries.

The International Herald Tribune reported Monday the United States has supplied satellite pictures of the Libyan plant to its allies as part of an effort to prove the factory is making banned chemical arms.

A West German intelligence source, who spoke to the newspaper on the condition of anonymity, said Bonn received the CIA photos in the past three weeks.