Delegates to the sixth assembly of the World Council of Churches yesterday condemned the production and deployment of nuclear weapons, by Eastern or Western bloc nations, as a "crime against humanity."

But a statement on the conflict in Afghanistan gave the Soviet Union little more than a slap on the wrist, despite efforts of Pakistani, West European and U.S. delegates to toughen the document, news services reported from Vancouver.

The resolution on Afghanistan passed after an emotional debate simply endorsed efforts by the United Nations to settle the conflict there, called for Soviet troop withdrawal "in the context of an overall settlement" and called for "an end to the supply of arms to opposition groups from outside," a reference to reported U.S. aid to Afghan resistance fighters.

In the most dramatic and divisive debate of the 18-day assembly, which concluded yesterday, Bishop Gunnar Lislerud of Norway led efforts to amend the resolution and condemn the Soviet role in Afghanistan. Lislerud called the Afghan guerrillas "a liberation movement" and said the council must "be in solidarity with suffering and oppressed people."

Anglican Bishop Alexander Malik of Pakistan also assailed the statement as weak and unbalanced, particularly in light of a pending statement on Central America that offered sharp criticism of U.S. policy and actions.

"Are the Afghans not human," Malik challenged, "or is it because they are not Christians?"

An amendment calling for immediate Soviet withdrawal was defeated by a vote of 306-278, after an hour of debate that included threats from a Russian Orthodox representative that his delegation would have to withdraw from the council if the amendment critical of Soviet policy was passed. The final resolution was adopted by a 479-121 vote, with 140 abstentions reflecting the uncertainty many delegates felt on the issue.

The action is expected to provide fuel for critics of the World Council of Churches who charge that it follows a double standard, turning a blind eye to human rights violations by the Soviet Union while sharply criticizing the West. Council officials counter that criticism of the Soviet Union would bring reprisals against the Russian Orthodox Church, while churches in democratic nations face no such hazards.

"The bottom line, is, who has the most to lose," explained council staffer John Bluck, "and that is the Russians."

In the nuclear statement, the 835 delegates urged the 300 member churches to oppose U.S. deployment of cruise and Pershing II missiles in Western Europe later this year, but also called for "major reductions" of Soviet intermediate-range missles.

The statement supported a mutual and verifiable freeze on nuclear weapons testing, development and deployment; completion of a comprehensive test-ban treaty, and completion of the Geneva nuclear arms reduction negotiations.

A statement on South Africa condemned the system of racial separation known as apartheid as "heretical" and called for worldwide and obligatory sanctions and a "real oil embargo" against the South African government.

On the Middle East, the assembly asked member churches to encourage talks between Israelis and Palestinians and called for greater awareness of the "urgent and just" Palestinian cause.