The president of Estonia defended his republic's fight for greater autonomy Wednesday after legislators denounced its declaration of sovereignty during heated debate over proposed constitutional changes.

Arnold Ruutel addressed the 1,500-member Supreme Soviet on the second day of the parliament's debate over reforms put forward by President Mikhail Gorbachev last month. Gorbachev says the 120 articles of legislation are the first major step toward a political system based on law, not central dictate.Ruutel told fellow deputies that economic and environmental problems prompted Estonia's declaration of sovereignty Nov. 16 over all internal affairs and its demand to review all new Soviet legislation.

Ruutel said he appreciated some of the amendments to Gorbachev's proposed reforms that were announced Tuesday, as well as plans to "widen and defend the sovereign rights of republics" in the next stage of reform. But he indicated Estonia still is not satisfied with the plan being debated.

The reforms are to be voted on Thursday.

In particular, Ruutel said Estonia would prefer to retain the Supreme Soviet, or parliament, rather than having the Soviet Union's 15 republics create a Congress of People's Deputies.

The congress concept is the base of Gorbachev's political reform.

After nearly three hours of open session, the Presidium, the nation's highest executive body, and two committees of the Supreme Soviet met in closed session to discuss suggestions made by deputies.

Ruutel did not mention statements of other Estonian leaders, who have indicated they plan to ignore last week's action by the Presidium of the Supreme Soviet nullifying Estonia's sovereignty declaration.

Many deputies echoed some of Estonia's complaints about the restructuring, but most of the speakers berated the small republic for passing a constitutional amendment giving it the right to veto Soviet laws.

The Estonian action "undermines the unity and principles of our multi-national state," said a deputy from Vladimir, a town about 120 miles east of Moscow. "These are anti-social actions," he said.

Some deputies apparently misunderstood Estonia's action. One speaker complained the republic had already canceled all Soviet laws.

Most national newspapers have published criticism of the Estonian action without explanation of the changes made by the republic in its law.

At Tuesday's session, Gorbachev bowed to criticism of his proposed reforms, saying he would accept tighter limits on presidential power and try to accommodate the republics seeking greater autonomy.