The widely heralded six-point plan to improve the conditions of nonwhite employees of American companies in South Africa has elicited only new frustration from local blacks who, generally, are not impressed with the "statement of principle" of 12 American companies.

"It looks good on paper, but in practice it means only minor, token changes," a prominent black employee at one of the 12 U.S. companies explained.

"It'll still be years before the steps bring significant results. That would have been fine a decade ago. Now it's not enough.

"If that's the only kind of pressure American businesses are willing to make, then I can see we can't rely on them as a major force for change."

Some whites have also criticized the American companies' announcement Tuesday. The liberal Rand Daily Mail newspaper editorialized:

"By almost any standards the six-point 'statement of principle' presented . . . this week by 12 leading American companies with operations in this country is unexceptional."

The influential magazine Financial Mail added:

"There is a genuine question as to whether the recent anti-apartheid gesture by the U.S. firms was aimed more at the White House and liberal American stockholder groups than at the Vorster government and its policies."

Meyer Feldberg, dean of the University of Cape Town's business school, said the move did not represent major changes in American business policy, speculating that the program was announced because of a fear that the new Carter administration would demand disclosures about the operations and pay-scales of branches in South africa.

The six-point plan was a means of buying time, avoiding pressure for a more radical and meaningful commitment to change, Feldberg said.

The controversial statement of principle bascially commits the American companies to:

Elimination of all segregated facilities in factories and offices, including canteens, rest rooms and showers.

Equal pay for equal work.

Equal advancement opportunities.

Increased promotion of blacks to management and supervisory capacities.

Active training programs to prepare black for advancement into senior positions.

A substantial improvement of employees' lives outside work in areas such as housing, transport, schooling and recreation.

After the announcement, Denis Sever the announcement, Denis Sevenoaks of International Telephone and Telegraph, said that 90 per cent of the 360 Americans companies with South African branches were already fulfilling most of the six points.

The major criticism of both blacks and whites in that the "manifesto" - as it has become known here - does not come to grips with the key issue: the question of trade unions for blacks.

As the Financial Mail explained: "Not only does continuing refusal by U.S. (and other) companies to recognize African unions constitute to recognize African unions constitute a perpetuation of racial discrimination; equally important, many of the problems which the manifesto seeks to tackle arise in large part from the fact that Africans are denied collective bargaining rights."

Another major criticism is that "equal pay for equal work" does not deal with the basic problem: that blacks, by and large, do not have many opportunities to achieve equal rank with whites.

"There are few times that this commitment will be tested since whites dominate the top jobs and blacks are usually at the bottom," a local personnel manager of a major American company said.

"First of all, the job reservation act reserves the top jobs for whites, which makes it difficult for a black to get a high level job whatever his abilities.

"Secondly, the education facilities for blacks are notoriously poor. Until the issue of general black training and education is dealt with - and that means the broad picture, not just special programs for a few lucky ones - the commitment is meaningless."

Perhaps the greatest cynicism about the American companies' statement was evoked when Minister of Interior and Information Connie Mulder Praised the move. In Parliament recently, Mulder said.

"The authorities welcome their declared intent to give impetus to existing extensive development programs already in operation in South Africa."

As a result of these existing programs, Mulder said, the South African black found himself "outstripping his counterparts on the African continent and many other areas of the world in all fields of human endeavor."