Yevsey Liberman, a controversial Soviet economist who provided the main ideas for an abortive attempt to restructure the Soviet economy in the 1960s, has died at age 84, it was reported here.

An obituary published in an obscure Siberian monthly journal did not give the date of Liberman's death and there was speculation among western diplomats that his passing had been ignored for months. The February edition of the Novosibirsk journal Eko, which arrived here recently, went to the printers on Nov. 5 last year and its contents were approved by the censors Jan. 5.

Liberman had been thoroughly disliked by the party bureaucracy and was denied membership in the Soviet Academy of Sciences. He lived in obscurity in Kharkov, in the Ukraine, where he was a professor at the University of Kharkov.

In its obituary, Eko hailed Liberman as a "great Soviet scientist" and described his reform proposals as reflecting "the collective wisdom of the party."

Western observers interpreted the delayed publication of Liberman's obituary in Eko as reflecting a growing strength of reform-minded elements in the Soviet establishment. Although he was well-known in this country, no other Soviet publication has reported his death.

It was under Nikita Khrushchev that Liberman, in a 1962 article in the Communist Party newspaper Pravda, advanced proposals for decentralizing management and introducing profit and other economic tools to stimulate the economy.

Liberman did not challenge the fundamental Marxist tenet of public ownership of the means of production. But he saw plenty of room for innovation by using economic tools normally associated with capitalist economies.

After the fall of Khrushchev in 1964, Premier Alexei Kosygin used Liberman's ideas in an effort to restructure the economic system. But Kosygin was reluctant to take a bold step and watered down most of Liberman's proposals.

Kosygin's plan for change was thwarted by its natural opponents in the vast government and party bureaucracy who saw in it a threat to their jobs and authority. Liberman not only assigned greater importance to profitability and sales, but also proposed direct links between state enterprises and regions. This would mean that the Moscow bureaucracy, which now runs this vast economy, would become superfluous.