The senior senator from Pennsylvania, Republican John Heinz, moved yesterday to block the nomination to the U.S. Civil Rights Commission of a Philadelphia minister who says he opposes the Equal Rights Amendment and busing to integrate public schools, and that homosexuals do not have a civil rights cause.

Heinz's move came as women's, civil rights and gay groups also called on President Reagan to withdraw the nomination of B. Sam Hart, a black radio evangelist who has no apparent ties to the Republican Party or any civil rights group in his home city.

There were also indications of uncertainty over the nomination in the administration. No one in the White House wanted to claim responsibility yesterday for Hart's selection. E. Pendleton James, White House personnel director, refused to return telephone calls on the matter for the second consecutive day.

Hart was recommended for a spot on the five-member commission by right-wing religious groups. They persuaded a number of conservative Republicans, including Senate Judiciary Chairman Strom Thurmond (S.C.) and Rep. Trent Lott (Miss.), to recommend Hart.

The nomination wasn't cleared through political channels, a fact that caused embarrassment among Pennsylvania Republicans. Transportation Secretary Drew Lewis, who usually passes on Pennsylvanians being considered for patronage jobs, wasn't consulted. Pennsylvania's junior senator, Republican Arlen Specter, who said he had never heard of Hart during a lifetime in Philadelphia politics, wrote Reagan to protest the procedure.

Hart created a storm of controversy during a 15-minute press conference Wednesday by saying he opposes the ERA and busing as a means of integrating schools. He also said he does not consider that homosexuals have a civil rights cause.

Seldom has a Reagan nominee alienated more people in such a short time. Several women's, civil rights and gay groups yesterday claimed that naming him to the commission was "like putting the fox in the hen house."

"I feel almost speechless. He is hostile to all the groups the commission is supposed to serve," said Eleanor Smeal, president of the National Organization for Women. "His appointment is a tragic departure from tradition. Both Republican and Democratic administrations in the past have respected the commission's role as a force for equality."

"The commission is the watchdog and conscience of the federal government," said William Taylor, a former executive director of the panel who now heads the Center for National Policy Review at Catholic University. "It was set up to bring independent information and insight into an area of great emotion.

"They are belittling the agency with this nomination. The message is they regard its functions as trivial."

Gay groups took issue with Hart's comments on homosexuality. On Wednesday he said that "homosexuals are not born," adding later that they have chosen their way of life. "They can repent like other sinners," he said.

Stephen Endean, executive director of the Gay Rights National Lobby, said Hart's remarks show that he "operates on misconception and ignorance. He seems to think someone gets up in the morning and decides that day to be a homosexual. That flies in the face of all scientific evidence."

A spokesman for Heinz said he had asked Judiciary Chairman Thurmond to put an indefinite hold on Hart's nomination. Although Heinz didn't categorically come out against the nomination, the aide said the senator had grave doubts about it and "will look very hard at Rev. Hart's positions on the issues."

To make matters worse, Hart's hometown newspaper, the Philadelphia Inquirer, called the nomination a "gross civil rights affront" and recommended that Reagan withdraw it.

Meanwhile, Republican J. Clay Smith resigned without explanation as acting chairman of the Equal Employment Opportunity Commission. Smith, a Carter administration appointee, has clashed openly with various administration officials, including William Bradford Reynolds, head of the Justice Department's civil rights division.

"He may have had enough," a spokesman said. "I don't know."