The five Western nations working toward negotiated independence for Namibia ended two days of talks here today with a brief communique indicating initial acceptance of a U.S. proposal that would reorder independence steps already agreed to by the U.N. Security Council.

At the same time, the statement by the United States, Britian, France, West Germany and Canada reaffirmed their belief that the four-year-old Security Council Resolution 435 provides a "solid basis" for a transition to independent rule in the South African-controlled territory.

Although the comminuque did not mention specific changes in the resolution's plan, which calls first for the election of a constituent assembly in Namibia that would then draft a constitution, it said that the representatives had "agreed that expeditious progress toward a settlement would be enhanced by measures aimed at giving greater confidence to all of the parties on the future of Namibia."

Diplomats involved in the talks said that the phrase referred to a U.S. proposal to draft a constitution first that would guarantee minority rights in Namibia and would be agreed to by contending forces there, and then elect an assembly. The implied agreement by the other four members of the "contact group" to continue "intensive consultation" on the issue was considered at least a partial victory for one of the key points of the Reagan administration's emerging policy on southern Africa.

[At a Security Council debate today on demands by black African nations for a resolution imposing sanctions against South Africa for its refusal to grant Namibia independence, the United States and Britian requested more time to negotiate.]

The U.S. envoy to the London talks was Chester Crocker, Reagan's nominee as assistant secretary of state for African affairs, who stopped here after a 12-nation African tour.

Crocker reportedly suggested the new independence arrangement, which is similar to the British-backed plan in Zimbabwe, during his trip and found uniform opposition from black African governments.

South Africa, however, has expressed interest, since Pretoria fears that the election-constitution scenario would give victory to the Southwest Africa People's Organization, known as SWAPO, now locked in a guerrilla war against South African forces in Namibia.

A U.N. conference on Resolution 435 in Geneva in January fell apart because of South African intransigence on the plan as it stood.

Various diplomats involved in the London talks said there was "broad agreement" on all major issues after 18 hours of meetings. One said they realized that the U.N. plan as it stands is "simply not salable."