Kremlin leader Mikhail Gorbachev on Tuesday condemned repression and authoritarianism under past Soviet leaders and urged the country's federal parliament to back his political reforms.

In a speech to a session of the Supreme Soviet, expected to vote itself out of existence in a reshaping of legislative power, Gorbachev said there would be guarantees for democracy under the new electoral system he was promoting."The principle of collective leadership, traditional for the Soviet system, is preserved in dealing with state problems of key importance," Gorbachev told 1,500 deputies in the Grand Kremlin Palace in a 70-minute speech.

He told the session, widely accepted as marking a major turning point in the 71-year-history of the Soviet Union, that the country had had to pay a huge human, political and material cost for violations of democracy in the past.

"Since the early 1930s," he declared in a reference to the bloody rule of Josef Stalin, "authoritarian methods of power were established and mass repressions and other violations of socialist legality became widespread."

Ordinary workers, the 57-year-old Kremlin leader said, had been cut out of the management of state and public affairs and party and state bureaucrats had pushed elected bodies like the Supreme Soviet itself aside.

"All this resulted in the ossifying of the political system. From a driving force in society it began to turn into a brake on development," he said, addressing the deputies from a rostrum under a statue of state founder Vladimir Lenin.

The session was called to discuss a package of proposals to create a new two-level parliament with real power in determining policy and controlling government bodies and to set up a multicandidate electoral system.

The proposals emerged from a party conference in July and have been widely debated in the Soviet media and at public meetings across the country since they were published in draft form in late October.

But they have aroused considerable controversy, with many strong supporters of Gorbachev's "perestroika" program to reshape Soviet society arguing they had been drafted in haste and needed more discussion.

The drafts also sparked fears in several of the country's 15 republics that central control would be tightened, leading Baltic Estonia's own parliament to vote itself the right to veto on its own territory any legislation passed in Moscow.

Gorbachev, in a dark suit and wearing a white shirt and red tie, implicitly rejected the Estonian action as he urged the deputies to understand that political reform had to be launched quickly and could not be further delayed.

"We have always condemned extreme centralization, but we should not get carried away by another extreme," said the Kremlin chief, who during the weekend de-nounced Estonia's extension of its sovereignty within the union as unacceptable.

But the Kremlin chief held out an olive branch to the restless Baltic republic, whose neighbors in Latvia and Lithuania as well as parliaments in Transcaucasian Georgia and Armenia have also sought changes to the drafts.