MOSCOW, JUNE 20 -- Soviet President Mikhail Gorbachev, frustrated by criticism from his chief conservative rival and other members of the Communist old guard, hinted today that he could leave his post as head of the party next month at its 28th national congress.

After listening to a number of speeches chastizing him for weakening the party since taking power in 1985, Gorbachev told the founding congress of the Russian republic's new Communist Party organization: "You know, I think a lot of comrades are treating the general secretary of the party and the president rather lightly. It's not just a question of me personally. Tomorrow or in 10 days or 12 days there could be another general secretary, or chairman of the party. To condemn and make accusations, you ought to a understand a great deal more."

Gorbachev's strongest critic today was Yegor Ligachev, the leading conservative on the party's ruling Politburo. Ligachev intimated broadly that Gorbachev ought to give up his party position and criticized him for bypassing the Politburo to make important decisions on economic reform, the German question and Soviet policy in Eastern Europe.

Ligachev, according to official reports, bemoaned "the collapse of the socialist commonwealth" and told the Russian party gathering that "the positions of imperialism have strengthened incredibly." He also accused "anti-socialist elements" of trying to weaken and "ultimately destroy from within the Communist Party and the Socialist Union of Republics."

In recent months, as the party monolith has continued to crumble, Ligachev has become more open about his opposition to Gorbachev's endorsement of a market economy and his decision to give tacit encouragement to the democratic revolts in Eastern Europe. Socialism, Ligachev told Moscow Radio today, "suffered a defeat in {Eastern Europe} . . . but I am sure this is a temporary setback and in the end the socialist idea will prevail."

Gorbachev, who was elected by an overwhelming legislative vote last March to the powerful new post of executive president, has pledged to switch all real political power from the party to the government, considerably weakening the importance of the post of general secretary, once the country's most important office.

High-ranking party sources said Gorbachev would like to relinquish his party position to devote more time to his presidential duties and to provide himself some distance from the increasingly unpopular party. But, they said, Gorbachev is fearful that there are no other party leaders capable of keeping conservatives in line.

In a sense, one of Gorbachev's strongest tools to keep order within the party is traditional "party discipline," under which leaders and apparatchiks must follow strict hierarchal rules of behavior.

Over the past year, Gorbachev has reportedly mentioned several times in closed meetings of the party's policy-making Central Committee that he might resign his party post, but it was unclear if these were serious suggestions or political tactics. Asked about today's remarks, Russian party spokesman Alexander Lebedev said that Gorbachev's words "seem to give no special ground for discussing the prospect for the withdrawal."

Even if Gorbachev is not seriously considering stepping down as party head, his comments today reflected a wide ideological and political gap between reformists in the top party leadership and the vast conservative layer of provincial leaders who dominate the party's middle ranks.

Delegates to the Russian party congress came from all across the vast republic, the priesthood of a dwindling faith talking desperately of restoration, battling against extinction.

Outside the Kremlin gates, few show much concern for the prospects of the new Russian party apparatus. The prestige of the Communist Party generally is down, and the Russian organization is filled with the officials whom much of the public scorns most -- party chieftains of the country's countless regions and districts.

But inside the Kremlin's Palace of Congresses, the Russian party congress is the scene of an almost ecclesiastical debate. As Gorbachev talks triumphantly of the historic rejection of the Stalinist legacy -- a reformation "comparable to the most radical events in world history" -- army generals and provincial officials ask him, in essence, are we really a Communist Party any longer? And what is communism or socialism in 1990? These are voices of an old guard whose world and language are slipping away from them.

At today's session, a Russian factory worker accused the leadership of allowing the rise of "too much sex and pornography." A Siberian party leader, Alexander Melnikov of Kemerovo, said a "cult of personality" had sprung up around Gorbachev and that the party leadership was indiffrent to the woes of working people. The party chief in the southern city of Krasnodar, Ivan Polozkov, bemoaned the lack of "discipline" in society and attacked by name Gorbachev's closest ally in the leadership, Alexander Yakovlev.

The applause for Gorbachev has been, at most, polite. But when an army general, Albert Makashov, took the lectern Tuesday to indict the leadership for ceding its influence in Eastern Europe and the liberal press for having the gall to criticize military spending, the hall broke into applause and cries of "That's right!" As the camera panned over the audience, television viewers saw the beaming faces of military leaders and provincial party chiefs.

Polozkov of Krasnodar, especially, has emerged as a hero of conservatives in the party. Nina Andreyeva, a Leningrad chemistry instructor who caused a sensation two years ago when her article in a Russian newspaper laid down a kind of neo-Stalinist party line, says that Polozkov is a leading defender of "classic" Marxism-Leninism, a "rare genius." At the same time, Andreyeva attacks Gorbachev, Yakovlev and others in the reformist wing of the party for introducing a quasi-capitalist economy.

Some conservatives are portraying the upcoming national congress in historic terms, invoking the example of the party's fractious second congress in London in 1903. At that session, Lenin's credo of party discipline and dogmatic Marxism led to the rise of his majority Bolshevik wing and a split with the so-called Mensheviks. In the conservative view, Gorbachev is playing the historical role of a "Menshevik revisionist."

Andreyeva, the leader of a conservative front called Yedintsvo, or Unity, told Radio Moscow: "We think that if the 28th Party Congress buries the party in a Menshevik {liberal} embrace, we must quit the party and raise the question of founding a communist party of Bolshevik Leninists. We are already drafting a program and the rules of such a Bolshevik party because we believe that it is unnatural for a Communist to be in the same party with revisionists" such as Gorbachev.

Some of the leading reform radicals in the party already are looking elsewhere. The new president of the Russian republic, Boris Yeltsin, said in the party newspaper Pravda today that he is considering "suspending" his party membership after the Russian party congress "to defend equally the interests of all the people in Russia." Members of a reform-advocating party group called Democratic Platform say they will leave the party if the July national congress fails to end party control over workplaces, the army and the KGB.

In the last five years, Gorbachev has done so much to reroute Bolshevik ideology that he has rendered words like "socialism" and "communism" meaningless to party faithful. Gorbachev says he is a "convinced Communist" seeking to decentralize the state, denationalize 60 percent of state property in three years, end suppression of religion and reestablish private and cooperative property.