Secretary of State George P. Shultz said yesterday the administration is considering taking new measures against South Africa short of "punitive economic sanctions" and is consulting Congress and U.S. allies in hopes of working out a coordinated approach.

Shultz's statement was the latest step in a continuing shift in administration posture following the broadly negative reaction here and abroad to President Reagan's policy speech on South Africa last Tuesday.

A senior White House official said the reaction to Reagan's speech had created an urgency to take new measures. Those under consideration, he said, include cancellation of U.S. landing rights for South African airlines and changes in U.S. consular arrangements to make official or semiofficial South African travel here more difficult.

Another move being considered, the official said, is the dispatch of a special presidential envoy to see South African President Pieter Botha and black leaders such as Oliver Tambo, acting president of the African National Congress.

Reagan is also weighing appointment of a new U.S. ambassador to Pretoria, with a selection likely next week, White House officials said. The two leading candidates, both endorsed by Shultz, are reported to be U.S. Ambassador to Liberia Edward J. Perkins, 58, and U.S. Ambassador to Denmark Terence A. Todman, 60. Both are career diplomats who are black.

Reagan's address Tuesday urged Congress and the allies "to resist this emotional clamor for punitive sanctions" against South Africa. "If Congress imposes sanctions, it would destoy America's flexibility, discard our diplomatic leverage and deepen the crisis," Reagan declared.

Shultz's remarks yesterday, like others by Reagan and White House officials earlier, drew a distinction between "additional punitive, really important economic sanctions," which the administration continues to oppose, and other measures affecting "South Africa's relation with the rest of the world," which the administration is considering.

Shultz said he is "in close touch" with Sen. Richard G. Lugar (R-Ind.), chairman of the Senate Foreign Relations Committee, about measures short of major and punitive sanctions. Shultz added that the administration also hopes to work out a coordinated approach to action with U.S. allies because "something done on a coordinated basis has greater potential impact than something done unilaterally."

The secretary of state, apparently referring to congressional pressure for swift action, said it may not be possible to postpone new measures until coordination is achieved.

Lugar, according to a spokesman, has held several conversations with Shultz since the secretary's embattled appearance before the Foreign Relations Committee Wednesday. Lugar was said to be in the process of consulting other members of Congress and drawing up a proposal to be circulated on Capitol Hill Monday and submitted to the committee for action Tuesday.

Among the measures under consideration, according to Lugar's press secretary, Mark Helmke, are a ban on airline landing rights for flights to and from South Africa, denial of visas and consular services to South African government officials and those of state-owned companies, freezing of U.S. bank deposits of South Africans, a ban on U.S. bank loans and possible restrictions on imports of South African coal and products of South African state-owned firms.

In addition, Lugar is considering putting into law the limited sanctions adopted administratively last September by Reagan under congressional pressure. These will expire Sept. 9 unless a new executive order is issued.

Assistant Secretary of State Chester A. Crocker, an architect of U.S. policy in Africa, is to fly to London early next week to meet British Foreign Secretary Geoffrey Howe, currently on a mission to South Africa that is accorded great importance by U.S. officials.

Howe, who is expected to meet Botha in Pretoria Tuesday, is scheduled to return to London Wednesday. Under the current timetable, the Senate Foreign Relations Committee is likely to be well along in its work on new sanctions by then. Staff writer Lou Cannon contributed to this report.