The Soviet Union and Czechoslovakia today launched a sharp counter-offensive against the United States over human rights at the conference reviewing East-West detente here.

The Eastern bloc delegates illustrated their points by painting a lurid picture of life in New York City, stressing unemployment, crime and homelessness.

In statements that were clearly coordinated beforehand, the Soviet and Czechoslovak delegates to the 35-nation European security review conference depicted tha American way of life as dominated by unemployment, racial discrimination and violent crime.

Chief Soviet delegate Yuli Vorontsov argued that the United States was guilty of "hundreds of thousands of violations" of the 1974 Helsinki Declaration and had no moral rights to critize the human rights record of other countries.

The speeches represented the strongest reaction so far to repeated and so far unanswered, American charges against the Soviet Union and Czechoslovakia. Until last week, Soviet delegates had refrained from rising specific cases of alleged human rights violations in the United States on the grounds tha this would constitute interference in another country's internal affairs.

There appears to have been a change of tactics, however, following a tough sppech Wednesday by chief U.S. delegate Arthur Bolgerg in support of proposals tha would strengthen the humanitarian proposals of the Helsinki final act. Vorontsov described the statement, which raised issued such as the imprisonment of sissidents in the Soviet Union and the harassment of journalists in Czechoslovakia, as "crude, provocative, and hypocritical."

The Soviet counterattack concentrated on alleged economic and social injustices in the United States.

Quoting extensively from Western newspaper stories, chief Czechoslovak delegate Richard Dvorak described a sick, vicious society that was unable to meet the basic human needs of its citizens. He said it was clear that "contemporary America violates human rights massively."

In sombre tones, Dvorak referred to the case of an anonymous old woman in Manhattan who was afraid to leave her apartment, even to buy food. According to a West German newspaper, he said, the old woman was murdered when she went to her mail box.

Retelling the story, the Czechoslovak delegate asked whether this was in accord with Article 3 of the Universal Declaration on Human Rights which guarantees the right to life, liberty, and security of person. The signatories of the Helsinki accord are also pledged to respect the Universal Declaration.

"Twenty old people were killed in 1975 in Bronx district alone." Dvorak said. "Thousands were beaten, raped, or roped to bedposts. This is the dreadful view of a society whose representative is so resolutely emphisizing human rights here, but not in his own country."

The Czechoslovak quoted former mayor John V. Lindsay as calling New York in 1973 "a city if terror."

Dvorak also alleged American violations of Article 7 of the Universal Declaration which guarantees equality before the law. He described prison sentences totaling more than 280 years against 10 people following race riots in Willmington, N.C. in 1971 as a "typical example of racist discrimination."

Dvorak quoted a passage in a book by the late civil rights leader Martin Luther King Jr. alleging government disregard for equal rights and then added: "It is well known that Mr. King was murdered as an inconvenient critic of the American society."

He concluded with a quotation from the Gospel of St. Mattehew: "Why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye?"

The Czechoslovak delegate described as "astounding" the fact that in the world's richest country there were more than 26 million people officially described as poor He said nine out od every 10 Americans could not afford hospitalization and that 15 per cent of the black population was permently unemployed

The clear conclusion, Dvorak added, is that "the authorities of the United States are, in fact, not concerned with human rights."

Exercising his right of reply. Ambassador Goldberg said he had stated repeatedly that the U.S. record on human and economic rights was not perfect.

"But our country's record of achievement in both areas is far better than the records of Soviet and Czechoslovak speakers."

Privately, U.S. officials brushed aside repeated Soviet warnings of a possible breakdown in the conference if polemics over human rights continue. They say they intend to go into greater detail as the meeting, now in its sixth week, gets down to a detailed discussion of new proposals.

Some Western and Neutral delegates, however, fear that the Soviet Union could use its power of veto to block progress in the three committees, dealing with European security, economic cooperation and human rights.