A House chairman urged government officials Friday to block action on a $92 million loan to a Nevada company whose rocket-fuel chemical was found in a Dutch harbor en route to Iran.

James Fletcher, chairman of the National Aeronautics and Space Administration, agreed to consider freezing action on the loan in a conversation with a House committee chairman, congressional aides said.Rep. Robert A. Roe, D-N.J., chairman of the House Science, Space and Technology Committee, urged Fletcher to halt approval of the deal, according to a committee staff member who asked not to be identified by name.

The aide quoted Roe, who was in New Jersey, as saying Fletcher had told him NASA has found no evidence that the Nevada company, Pacific Energy Production Co., knew that the chemical it produced was bound for Iran.

Roe replied in the telephone conversation with Fletcher that the committee disagreed, according to the aide. He said the panel would hold hearings on the controversy following next week's Easter congressional recess.

Acting on a tip from the Customs Service, Dutch police seized an Iranian-flag freighter in the port of Rotterdam last year. It was carrying ammonium perchlorate, an oxidizer used in solid rocket fuels such as those powering the space shuttles' solid fuel boosters, Trident submarine-launched ballistic missiles and a host of tactical weapons.

Executives of Pacific Energy Production, based in Henderson, Nev., outside Las Vegas, said they did not know anything about plans to send the product to Iran. They said they had sold it to an American subsidiary of a Swiss firm.

The $92 million loan is being arranged through a bank with NASA's aid to rebuild a Pacific Energy Production Co. plant that exploded on May 4, 1988. The company is one of two in the United States that produce the chemical, and NASA has been concerned that, with the supply halved, a shortage could develop.