House Democrats, meeting in closed caucus, yesterday unanimously approved a resolution endorsing the use of economic sanctions against South Africa to force an end to the white government's system of racial segregation, known as apartheid.

Meanwhile, the Senate voted, 89 to 4, to condemn South African racial policies and request an administration report on an incident in the Eastern Cape region of South Africa in which police gunfire took at least 19 lives.

Senators voting against the measure were Barry Goldwater (R-Ariz.), Chic Hecht (R-Nev.), Jesse Helms (R-N.C.) and Steve Symms (R-Idaho). Sen. John P. East (R-N.C.) voted present.

Without specifically naming it, the House resolution rejects the Reagan administration's policy of "constructive engagement" in dealing with South Africa and states that the United States must distance itself more sharply from the "evil and unacceptable apartheid system."

It also calls on Congress to approve legislation introduced with bipartisan backing in both the House and Senate that would impose sanctions against South Africa, such as prohibiting Americans from making new bank loans or investments there. It would also ban computer sales to its government and would no longer allow the importation of Kruggerand gold coins from South Africa.

Another South Africa bill, which does not include such dramatic sanctions, has been introduced in the House by a group of conservative Republicans.