Libyan leader Muammar Quaddafi arrived here today for an official visit, his first since 1976, and Soviet President Leonid Brezhnev welcomed him as a true comrade and belittled charges by the Reagan adminstration that Moscow supports international terrorism.

Brezhnev underscored the Kremlin's new effort to blunt Washington's recent Middle East diplomacy by declaring in a Kremlin toast to Quaddafi that the stationing of U.S. troops in the Sinai as part of the Camp David peace process would be "a direct challenge to the Arab peoples."

Brezhnev, according to the Tass news agency, said, "Imperialists have no regard either for the will of people or the laws of history. The liberation struggles cause their indignation. They describe it as 'terrorism.'"

Imperialists, he said, "use any pretext for interference in others' affairs, for military expansion, and when there are no such pretexts, they create them artifically." He told his audience to "recall . . . how official Washington used the question concerning a group of American diplomats who were detained some time back in Iran. They have long since returned safely home but the powerful Navy brought to the Indian Ocean and Persian Gulf area allegedly for the rescue of the 'hostages' is to this day sailing in those waters, threatening neighboring states and universal peace."

Quaddafi, who looked tense despite frequent smiles during arrival ceremonies shown extensively on Soviet television, is here for a three-day visit that Western diplomats predict will concentrate on further arms shipments to Libya by Moscow, one of Quaddafi's principal weapons suppliers. s

Calling the Camp David agreements "collusion," Brezhnev emphasized the Kremlin's alignment with hard-line Arab states, saying that Moscow and the Arabs "from the very beginning" had called the Israeli-Egyptian accords the start of "knocking together a military block against the Arabs."

The Soviet position in the Middle East has been frozen since the accords but the Kremlin is trying to involve itself again. Jordan's King Hussein is scheduled to visit next month, and Palestine Liberation Organization leader Yasser Arafat, a frequent visitor, is expected soon as well.

Yesterday, Soviet Foreign Minister Andrei Gromyko ended talks with Kuwait's foreign minister, Sheik Sabah Ahmed Sabah, and a joint communique called anew for an international conference on the Middle East, a staple of the Soviet position.