Senior American officials indicated strongly today that the United States would veto any U.N. Security Council effort to impose economic sanctions on South Africa.

American diplomats here sought to persuade black African nations to go along with President Carter's six-month mandatory arms embargo on South Africa. Nevertheless, a number of African states appeared determined to press their tougher resolutions in a Security Council vote Monday.

Appearing in televised interview, Zbigniew Brzezinki, Carter's national security adviser, said the United States believed that "too many sanctions could be "counterproductive." He said that the United States hopes that the South African government would "correct" its repressive policies toward the blacks.

Informed sources said a consesus appeared to be forming within the 49-member African group over the weekend to seed a vote on broad sanctions - including a permanent arms embargo and a ban on investment and trade.

If this is then voted, they would accept the proposal of a renewable arms embargo as a fallback position.

Senior U.S. officials said that Britain and France had indicated that they would join in a veto on any attempt to impose broader sanctions on Pretoria.

In the television interview (CBS-Face The Nation), Brzenzinski voked concern about possible Soviet "intrusion" into South African affairs that could fuel racial conflicts and create a big power confrontation.

"And therefore it is in the interest of everyone concerned to take corrective measures soon enough," he said. "This is why we feel that sanctions are necessary, and this is why we feel that too many sanctions on too grand a scale could be counterproductive."

American diplomats here have told African colleagues privately that the United States would veto any move for broader sanctions against South Africa.

U.S. officials in weekend contacts with African delegates found them unwilling to shelve their resolution in favor of the proposed Western compromise.

"It's not just that they don't think our plan goes far enough," U.S. Ambassador Andrew Young said in a television interview (ABC - Issues and Answers). "They were thrilled at what President Carter said, but they are still looking around to see if there is a hitch somewhere. Some of the things that are in our resolution they look on with great suspicion."

African suspicions center on the fact that the Wetern arms embargo is of limited duration; that it excludes any ban on licensing arrangements that currently allow South Africa to produce such military items as Mirage jet warplanes, that it does not bar nuclear cooperation, and that the wording of the draft resolution fails to go far enough in explicitly labeling South Africa a "threat to international peace and security."

The United States, however, remained totally opposed to the imposition of economic sanctions on the Pretoria regime at this stage.

Brzenziski argued that U.N. action against South Africa at this stage had to be addressed to the specific events stemming from the death of black leader Steve Biko, and Pretoria's subsequent crackdown on black newpapers and activists.

Noting that South Africa had played a helpful role in Western efforts to achieve a peaceful transition to black majority rule in Rhodesia. Brzezinshi voiced fears that a total embargo against South Africa might "undermine" that cooperation.

"This is again one of the reasons why we feel that our response ought to focus on the specific events of the last week, and try to correct of them, rather than to go wholesale at the generic causes of the problem," he said.

"Our hope is the South African government will take the necessary corrective measures before the international community ostracizes it and before the situation becomes polarized."

Young also said that emotionally he would like to see sanctions include a ban on nuclear cooperation with South Africa, but that "partically things have gone too far that to be a realistic possibility."

"I think that South Africa has achieved . . . nuclear potential the extent of which we are not fully able to judge," Young said. "To cut things now would only encourage separate development. By maintaining some kind of relationship, we do have the possiblity of influencing them to sign the Nuclear Nonproliferation Treaty."

Both Young and Brzenzinski indicated that the United States is considering additional bilateral steps aimed at increasing pressure on Pretoria.

Brzezinski observed that the American ambassador to Pretoria, William Bowdler, who was recalled to Washington a week ago as a signal of U.S. unhappiness over the South African crackdown on blacks, would not be returning to his post as quickly as had been expected.

Bowdler had been scheduled to return to Pretoria within the next few days. "It may be a little later than that," Brzezinski said today.

"At some point, we expect he will go back," he added.