China today denied a report that it might provide Iran with sensitive nuclear technology and said all its dealings with other countries, including Pakistan, on nuclear issues are for peaceful purposes.

In answer to queries from reporters, the Foreign Ministry provided a statement saying the report was "groundless."

"China does not advocate nor practice nuclear proliferation, nor does it help other countries develop nuclear weapons," the statement said.

A report this week said the Reagan administration had received reliable intelligence reports that China discussed nuclear technology with the Iranians during a visit in June to Peking by Iran's Parliament speaker Hojatoleslam Ali Akbar Hashemi Rafsanjani. Intelligence concerning Rafsanjani's discussions was reported to have been described earlier this month in a closed briefing to the Senate Foreign Relations Committee.

Sen. Alan Cranston (D-Calif.), a critic of the U.S.-China nuclear cooperation pact signed this summer, said this week that China "has not shown, in its discussions of nuclear commerce" with Iran's Rafsanjani, "anywhere near the type of prudence we would expect."

Cranston accused the Chinese of exporting nuclear bomb-making technology to five nuclear "outlaw" nations -- Brazil, Argentina, Pakistan, Iran and South Africa -- after discussions between U.S. and Chinese officials concerning the importance of curbing such exports.

The Foreign Ministry statement confirmed that China has a peaceful nuclear cooperation agreement with Pakistan but denied a similar relationship with Iran. It was one of the few times that China has acknowledged having such a relationship with Pakistan. China's Vice Premier Li Peng did so in January in remarks relating to the development of a nuclear reactor for peaceful purposes inside China.

The statement said China's "cooperation in the field of nuclear energy with other countries, such as France, Federal [West] Germany, the United States, Brazil, Pakistan and Japan, whether ongoing or under discussion, serves and will serve only peaceful purposes instead of any nonpeaceful purposes."

Allegations that China helped Pakistan to design nuclear weapons caused the Reagan administration to delay submitting the U.S.-China nuclear pact to Congress until July. Unless rejected by a majority of the Congress, the agreement will take effect in January 1986.

Leading Chinese officials have given several assurances over the past year and a half that China does not practice nuclear proliferation. China has joined the International Atomic Energy Agency and recently expressed willingness to have certain nuclear facilities inspected.