The Reagan administration has told Pakistan that actions, not words, are needed to deal with the crisis of confidence caused by the arrest of a Pakistani native on charges he sought to illegally export sensitive U.S. material for Pakistan's nuclear weapons program, State Department officials said yesterday.

The U.S. message, delivered by Undersecretary of State Michael H. Armacost and U.S. Ambassador to Pakistan Arnold Raphel in conversations with Pakistani officials, did not specify what actions Pakistan should take to repair the situation and avert a cutoff of U.S. economic and military aid, according to the sources.

Among measures under discussion within the administration, the sources said, are Pakistani acceptance of the 1968 Nonproliferation Treaty; international inspection of its atomic facilities; arrangements for U.S. officials to check with certainty on the extent of Pakistan's enrichment of uranium to weapons-grade purity; and a government order prohibiting efforts to illegally acquire sensitive nuclear-related equipment and technology abroad.

A Foreign Ministry spokesman in Islamabad yesterday officially denied that his government had any connection with the alleged attempt by a Canadian citizen of Pakistani origin, Arshad Z. Pervez, to bribe a U.S. official and export a special steel alloy and other nuclear-related material from the United States to Pakistan.

"Neither the government of Pakistan nor any of its agencies sponsored any violation of the export laws of the United States," the Pakistani spokesman said.

Pakistani officials have said they have no information about Pervez, who was arrested last Friday in Philadelphia and is being held in jail without bond, or about a retired brigadier general, Inam ul Haq, named in court as Pervez's Pakistani client in the procurement attempt.

The Pakistani denials have not quieted administration concerns, however. Officials believe that information to be revealed in court in the Pervez case will point to the Pakistani atomic program as the prime mover of Pervez's efforts.

James D. Donohue, assistant U.S. Customs attache in Canada, told a magistrate's hearing in Philadephia Tuesday that at least 300 documents, including letters and cables, were seized by Canadian police last Friday in raids on Pervez's Toronto office and home.

In some of the documents, Donohue told the hearing, Inam told Pervez to put aside his personal interest in favor of national interest to obtain the U.S. material. In other documents, he testified, Inam emphasized that his negotiations for the material should be kept secret.

Jamsheed Marker, Pakistani ambassador to the United States, told Armacost Wednesday that Pakistan previously issued an order barring illegal procurement of sensitive material from the United States, sources said. Congress enacted a law in 1985 requiring a cutoff of U.S. economic and military aid to any non-nuclear nation such as Pakistan that seeks illegally to obtain U.S. nuclear-related material.

Pakistan's current $3.2 billion U.S. aid program runs out Sept. 30, and a new, six-year $4 billion aid program is scheduled to begin Oct. 1. The new program cannot begin, however, without a waiver of U.S. nonproliferation laws. Members of Congress had put the administration on notice in conversations this week that such a congressional waiver is in grave danger because of the Pervez case.

Armacost, with special responsibility within the State Department for South Asian affairs, is scheduled to visit Pakistan at the end of July on a previously-planned trip. Sources said his discussions with top Pakistani government officials could be crucial to future developments regarding the nuclear-materials issue as well as Afghanistan, and other sensitive aspects of U.S.-Pakistan relations.